Saturday, June 28, 2014

DECOLONIZATION OF AFRICA ---- HISTORY FORM FOUR

The decolonization of Africa followed World War II as colonized peoples agitated for independence and colonial powers withdrew their administrators from Africa.[1]
The only two world powers to officially and actively support African decolonization through the entire 20th century were the Soviet Union and the People's Republic of China — all others varied their opinions from the strong and stubborn defense of colonialism to a half-hearted support to fait-accompli situations.

Background

Main article: Scramble for Africa
During the Scramble for Africa in the late nineteenth century, Western European powers divided Africa and its resources into political partitions at the Berlin Conference of 1884-85. By 1905, control of almost all African soil was claimed by Western European governments, with the only exceptions being Liberia (which had been settled by African-American former slaves) and Ethiopia (which had successfully resisted colonization by Italy). Britain and France had the largest holdings, but Germany, Spain, Italy, Belgium, and Portugal also had colonies. As a result of colonialism and imperialism, Africa lost not only its sovereignty, but also control of its natural resources like gold and rubber. Europeans often justified this using the concept of the White Man's Burden, an obligation to "civilize" the peoples of Africa.[citation needed]
Critics say that the process of African decolonization from the 1950s to the 1970s turned what were relatively well-ordered and peaceful territories administered by the efficient bureaucracies and legal traditions of the Western European empires into violent, inefficient and corrupt socialist dictatorships or right-wing family dictatorships with little regard for international rule of law and human rights and riddled with civil-turf wars, barbaric political purges, mass refugee crises, famines and ethnic conflict.[2]

Causes

World War II saw the British African colonies support the Allies against the Axis powers, but with no mention of independence for African nations. German wartime propaganda had a part in this defiance of British rule. Imperial Japan's conquests in the Far East caused a shortage of raw materials such as rubber and various minerals. Africa was therefore forced to compensate for this shortage and greatly benefited from this change. Another key problem the Europeans faced were the U-boats patrolling the Atlantic Ocean. This reduced the amount of raw materials being transported to Europe and prompted the creation of local industries in Africa. Local industries in turn caused the creation of new towns, and existing towns doubled in size. As urban community and industry grew so did trade unions. In addition to trade unions, urbanization brought about increased literacy, which allowed for pro-independence newspapers.
On February 12th, 1941, United States President Franklin D. Roosevelt and British Prime Minister Winston Churchill met to discuss the postwar world. The result was the Atlantic Charter. It was not a treaty and was not submitted to the British Parliament or the Senate of the Unitated States for ratification, but it turned to be a widely acclaimed document.[3] One of the provisions, introduced by Roosevelt, was the autonomy of imperial colonies. After World War II, the US and the African colonies put pressure on Britain to abide by the terms of the Atlantic Charter. After the war, the British still considered their African colonies as "children" and "immature"; they introduced democratic government only at the local levels.
By the 1930s, the colonial powers had cultivated (sometimes inadvertently) a small elite of leaders educated in Western universities and familiar with ideas such as self-determination. These leaders, including leading nationalists such as Jomo Kenyatta (Kenya), Kwame Nkrumah (Gold Coast, now Ghana), Léopold Sédar Senghor (Senegal), and Félix Houphouët-Boigny (Côte d'Ivoire), came to lead the struggles for independence.

Timeline


Dates of independence of African countries

African countries in order of independence
Country[4] Colonial name Colonial power[5] Independence date[6] First head of state Independence won through
Libya Libya Italian Libya; Allied Military Administration Italy Italy
United Kingdom
United Kingdom
France
France
December 24, 1951 King Idris I Western Desert Campaign
Egypt Egypt British Egypt United Kingdom United Kingdom 1922/1936/1952[7] Sarwat Pasha, Farouk, 1952 Egyptian revolution[7]
Sudan Sudan Anglo-Egyptian Sudan United Kingdom United Kingdom[10]
 
Egypt
1 January 1956 Ismail al-Azhari Condominium ended
Tunisia Tunisia French protectorate of Tunisia France France March 20, 1956 Muhammad VIII al-Amin -
Morocco Morocco Protectorate of Morocco FranceFrance
Spain
Spain
April 7, 1956[11] Mohammed V Rif War, Ifni War
Ghana Ghana Gold Coast United Kingdom United Kingdom[12] Britain March 6, 1957 Kwame Nkrumah -
Guinea Guinea French Guinea (part of French West Africa) France France October 2, 1958 Sékou Touré -
Cameroon Cameroon Cameroun France France
United Kingdom
United Kingdom
January 1, 1960[13] Ahmadou Ahidjo UPC rebellion
Togo Togo French Togoland France France April 27, 1960 Sylvanus Olympio -
Mali Mali French Sudan (part of French West Africa) France France June 20, 1960[14] Modibo Keita -
Senegal Senegal part of French West Africa France France June 20, 1960[14] Léopold Senghor -
Madagascar Madagascar Malagasy Protectorate France France June 26, 1960 Philibert Tsiranana Malagasy Uprising
Democratic Republic of the Congo Democratic Republic of the Congo Belgian Congo Belgium Belgium June 30, 1960 Patrice Lumumba Congo Crisis
Somalia Somalia[15] British Somaliland
Italian Somaliland
United Kingdom United Kingdom
Italy
Italy
June 26, 1960
July 1, 1960
Muhammad Haji Ibrahim Egal
Aden Abdullah Osman Daar
-
-
Benin Benin French Dahomey (part of French West Africa) France France August 1, 1960[16] Hubert Maga -
Niger Niger Colony of Niger (part of French West Africa) France France August 3, 1960 Hamani Diori -
Burkina Faso Burkina Faso French Upper Volta (part of French West Africa) France France August 5, 1960 Maurice Yaméogo -
Ivory Coast Côte d'Ivoire Ivory Coast (part of French West Africa) France France August 7, 1960 Félix Houphouët-Boigny -
Chad Chad French Chad (part of French Equatorial Africa) France France August 11, 1960 François Tombalbaye -
Central African Republic Central African Republic Ubangi-Shari (part of French Equatorial Africa) France France August 13, 1960 David Dacko -
Republic of the Congo Republic of the Congo French Congo (part of French Equatorial Africa) France France August 15, 1960 Fulbert Youlou -
Gabon Gabon part of French Equatorial Africa France France August 17, 1960 Léon M'ba
Nigeria Nigeria British Nigeria United Kingdom United Kingdom October 1, 1960 [17] Nnamdi Azikiwe -
Mauritania Mauritania part of French West Africa France France November 28, 1960 Moktar Ould Daddah -
Sierra Leone Sierra Leone Sierra Leone United Kingdom United Kingdom April 27, 1961 Milton Margai -
South Africa South Africa Union of South Africa United Kingdom United Kingdom 1910/1931/1961[18] James Barry Munnik Hertzog -
Tanzania Tanzania[19] Tanganyika
Zanzibar
United Kingdom United Kingdom December 9, 1961
December 10, 1963
Julius Nyerere
Jamshid ibn Abdullah
-
-
Rwanda Rwanda part of Ruanda-Urundi Belgium Belgium July 1, 1962 Grégoire Kayibanda - [20]
Burundi Burundi part of Ruanda-Urundi Belgium Belgium July 1, 1962 André Muhirwa -
Algeria Algeria French Algeria France France July 3, 1962 Ahmed Ben Bella -
Uganda Uganda Uganda Protectorate United Kingdom United Kingdom October 9, 1962 Milton Obote -
Kenya Kenya Kenya Colony United Kingdom United Kingdom December 12, 1963 Jomo Kenyatta Mau Mau Uprising (debated)
Malawi Malawi Nyasaland Protectorate United Kingdom United Kingdom July 6, 1964 Hastings Kamuzu Banda -
Zambia Zambia Northern Rhodesia United Kingdom United Kingdom October 24, 1964 Kenneth Kaunda -
The Gambia The Gambia Gambia United Kingdom United Kingdom February 18, 1965 Dawda Kairaba Jawara -
Botswana Botswana Bechuanaland Protectorate United Kingdom United Kingdom September 30, 1966 Seretse Khama -
Lesotho Lesotho Basutoland United Kingdom United Kingdom October 4, 1966 Leabua Jonathan -
Namibia Namibia South West Africa South Africa South Africa October 27, 1966 (De jure)[21]
March 21, 1990 (De facto)
Sam Nujoma Namibian War of Independence
Mauritius Mauritius
United Kingdom United Kingdom March 12, 1968
-
Swaziland Swaziland Swaziland United Kingdom United Kingdom September 6, 1968 Sobhuza II -
Equatorial Guinea Equatorial Guinea Spanish Guinea Spain Spain October 12, 1968 Francisco Macías Nguema -
Guinea-Bissau Guinea-Bissau Portuguese Guinea Portugal Portugal September 24, 1973 Luís Cabral Guinea-Bissau War of Independence/Portuguese Colonial War
Mozambique Mozambique Portuguese East Africa Portugal Portugal June 25, 1975 Samora Machel Mozambican War of Independence/Portuguese Colonial War
Cape Verde Cape Verde
Portugal Portugal July 5, 1975
influenced by Guinea-Bissau War of Independence
Comoros Comoros French Madagascar, French Comoros France France
Madagascar
Madagascar
July 6, 1975
-
São Tomé and Príncipe São Tomé and Príncipe
Portugal Portugal July 12, 1975
-
Angola Angola Portuguese West Africa Portugal Portugal November 11, 1975 Agostinho Neto Angolan War of Independence/Portuguese Colonial War
Seychelles Seychelles
United Kingdom United Kingdom June 29, 1976 James Richard Marie Mancham -
Djibouti Djibouti French Somaliland France France June 27, 1977 Hassan Gouled Aptidon -
Zimbabwe Zimbabwe Southern Rhodesia United Kingdom United Kingdom April 18, 1980[22] Canaan Banana Lancaster House Agreement
Sahrawi Arab Democratic Republic Sahrawi Republic[24] Spanish Sahara;
Moroccan Sahara
Spain Spain;
Morocco
Morocco
February 27, 1976;
Independence not effectuated over most of the territory
El-Ouali Mustapha Sayed;
Mohamed Abdelaziz
Western Sahara War;
Saharawi
Intifada

See also

Notes

  1. Birmingham, David (1995). The Decolonization of Africa. Routledge. ISBN 1-85728-540-9.
  2. Africa 'better in colonial times', BBC News, 22 September 2004
  3. Karski, Jan (2014). The Great Powers and Poland: From Versailles to Yalta. Rowman & Littlefield. p. 330. ISBN 9781442226654. Retrieved 24 June 2014.
  4. Timeline list arranged according to current countries. Explanatory notes are added in cases where decolonization was achieved jointly or where the current state is formed by merger of previously decolonized states.
  5. Some territories changed hands multiple times, so in the list is mentioned the last colonial power. In addition to it the mandatory or trustee powers are mentioned for territories that were League of Nations mandates and UN Trust Territories.
  6. Date of decolonization for territories annexed by or integrated into previously decolonized independent countries are given in separate notes.
  7. On 28 February 1922 the British government issued the Unilateral Declaration of Egyptian Independence. Through this declaration, the British government unilaterally ended its protectorate over Egypt and granted it nominal independence with the exception of four "reserved" areas: foreign relations, communications, the military and the Anglo-Egyptian Sudan.[8] The Anglo–Egyptian treaty of 1936 reduced British involvement, but still was not welcomed by Egyptian nationalists, who wanted full independence from Britain, which was not achieved until the 1952 revolution. The last British troops left Egypt after the Suez Crisis of 1956.
  8. King, Joan Wucher (1989) [First published 1984]. Historical Dictionary of Egypt. Books of Lasting Value. American University in Cairo Press. pp. 259–260. ISBN 978-977-424-213-7.
  9. Robert O. Collins, A History of Modern Sudan
  10. Anglo-Egyptian Condominium Agreement of 1899, stated that Sudan should be jointly governed by Egypt Egypt and Britain, but with real power remaining in British hands.[9]
  11. Cape Juby was ceded by Spain to Morocco on 2 April 1958. Ifni was returned from Spain to Morocco on 4 January 1969.
  12. The British Togoland mandate and trust territory was integrated into Gold Coast colony on 13 December 1956.
  13. After the French Cameroun mandate and trust territory gained independence it was joined by part of the British Cameroons mandate and trust territory on October 1, 1961. The other part of British Cameroons joined Nigeria.
  14. Senegal and French Sundan gained independence on 20 June 1960 as the Mali Federation, which dissolved a few months later into present day Senegal and Mali.
  15. The Trust Territory of Somalia (former Italian Somaliland) united with the State of Somaliland (former British Somaliland) on July 1, 1960 to form the Somali Republic.
  16. Independent Benin unilaterally annexed Portuguese São João Baptista de Ajudá in 1961.
  17. Part of the British Cameroons mandate and trust territory on October 1, 1961 joined Nigeria. The other part of British Cameroons joined the previously decolonized French Cameroun mandate and territory.
  18. The Union of South Africa was constituted through the South Africa Act entering into force on 31 May 1910. On 11 December 1931 it got increased self-governance powers through the Statute of Westminster which was followed by transformation into republic after the 1960 referendum. Afterwards, South Africa was under apartheid regime until elections resulting from the negotiations to end apartheid in South Africa on 27 April 1994 when Nelson Mandela became president.
  19. After both gained independence Tanganyika and Zanzibar merged on 26 April 1964
  20. See Rwandan Revolution.
  21. UN resolution 2145 terminated South Africa's mandate over Namibia, making it de jure independent. South Africa did not relinquish the territory until 1990
  22. Unilaterally declared independence in 1965 as Rhodesia, followed by attempted Internal Settlement in 1979 as Zimbabwe-Rhodesia; both states were unrecognised by the United Kingdom. British-organised elections were held in early 1980 involving the Zimbabwe African Peoples Union and Zimbabwe African National Union as stipulated in the Lancaster House Agreement.
  23. UN General Assembly Resolution 34/37 and UN General Assembly Resolution 35/19
  24. The Spanish colonial rule de facto terminated over the Western Sahara (then Rio de Oro), when the territory was passed on to and partitioned between Mauritania and Morocco (which annexed the entire territory in 1979), rendering the declared independence of the Saharawi Arab Democratic Republic ineffective to the present day (it controls only a small portion east of the Moroccan Wall). The UN still considers Spain as administrating country of the whole territory,[23] awaiting the outcome of the ongoing Manhasset negotiations and resulting election to be overseen by the United Nations Mission for the Referendum in Western Sahara. However, the de facto administrator is Morocco (see United Nations list of Non-Self-Governing Territories).

References

  • Michael Crowder, The Story of Nigeria, Faber and Faber, London, 1978 (1962)
  • Understanding Contemporary Africa, April A. Gordon and Donald L. Gordon, Lynne Riener, London, 1996
  • Vincent B. Khapoya, The African Experience, Prentice Hall, Upper Saddle River, NJ, 1998 (1994)
  • Ali A. Mazrui ed. General History of Africa, vol. VIII, UNESCO, 1993
  • Kevin Shillington, History of Africa, St. Martin's Press, New York, 1995 (1989)
  • Diueter Rothermund, The Routledge Companion to Decolonization, Arlington & New York: Routledge, 2006

External links

INTRODUCTION TO TRIGONOMETRY



Introduction to trigonometry

As you see, the word itself refers to three angles - a reference to triangles.
Trigonometry is primarily a branch of mathematics that deals with triangles, mostly right triangles. In particular the ratios and relationships between the triangle's sides and angles. It has two main ways of being used:

1. In geometry

In its geometry application, it is mainly used to solve triangles, usually right triangles. That is, given some angles and side lengths, we can find some or all the others.
For example, in the figure below, knowing the height of the tree and the angle made when we look up at its top, we can calculate how far away it is (CB). (Using our full toolbox, we can actually calculate all three sides and all three angles of the right triangle ABC).

2. Analytically

In a more advanced use, the trigonometric ratios such as as Sine and Tangent, are used as functions in equations and are manipulated using algebra. In this way, it has many engineering applications such as electronic circuits and mechanical engineering. In this analytical application, it deals with angles drawn on a coordinate plane, and can be used to analyze things like motion and waves.
For example, a radio or sound wave can be described by an equation such as
y = sin(ax+b)
and when graphed might look something like the wave below. The values of a,b and c determine the wave's amplitude, frequency and phase shift.

Other trigonometry topics

Angles

Trigonometric functions

Solving trigonometry problems

Calculus

MWL JAPHET MASATU BLOG: TYPES OF NATIONALISM----- HISTORY FORM F...

MWL JAPHET MASATU BLOG: TYPES OF NATIONALISM----- HISTORY FORM F...: TYPES    OF    NATIONALISM I Part of a series on Nationalism Development [show] Core values [show] ...

AFRICAN NATIONALISM--- HISTORY FORM FOUR.

AFRICAN   NATIONALISM


African nationalism is a political movement for Pan-Africanism and for national self-determination.[1] Political interest began in the 1870s[2] and political organizations started to form in the 1890s.[1] In the years after World War II, African nationalism gained strength,[3] resulting in independence for Libya in 1951 and Ghana in 1957. All but six African countries were independent nation-states by 1966.[3] Edward Wilmot Blyden has been described as the founder of African nationalism.[4] Julius Nyerere defined African nationalism as a new kind of nationalism and that it is "meaningless, dangerous, is anachronistic if it is not at the same time pan-Africanism."[5]

See also

References

  1. African nationalism
  2. 17 African nationalism
  3. Exploring Africa
  4. Neuberger, Benyamin (1985). "Early African Nationalism, Judaism and Zionism: Edward Wilmot Biyden". Jewish Social Studies 47 (2): 151.
  5. Emerson, Rupert (2009). "Pan-Africanism". International Organization 16 (2): 290. doi:10.1017/S0020818300011061.

Further reading

  • Shepherd, George W., junior (1962). The Politics of African Nationalism: Challenge to American Policy. New York: F.A. Praeger.

THE ATOM ---- CHEMISTRY FORM FIVE.

THE   ATOM  -- CHEMISTRY   FORM  FIVE.


INTRODUCTION
Atom
A drawing of a Lithium atom. In the middle is the nucleus, which in this case has four neutrons (blue) and three protons (red). Orbiting it are its three electrons.
Lithium atom model
Showing nucleus with four neutrons (blue),
three protons (red) and,
orbited by three electrons (black).
Classification
Smallest recognised division of a chemical element

Properties

Mass: 1.66 x 10(−27) to 4.52 x 10(−25) kg
Electric charge: zero
An atom is the basic unit that makes up all matter. There are many different types of atoms, each with its own name, mass and size. These different types of atoms are called chemical elements. The chemical elements are organized on the periodic table. Examples of elements are hydrogen and gold. Atoms are very small, but the exact size changes depending on the element. Atoms range from 0.1 to 0.5 nanometers in width.[1] One nanometer is around 100,000 times smaller than the width of a human hair.[2] This makes atoms impossible to see without special tools. Equations must be used to see the way they work and how they interact with other atoms.
Atoms come together to make molecules or particles: for example, two hydrogen atoms and one oxygen atom combine to make a water molecule, a form of a chemical reaction.
Atoms themselves are made up of three kinds of smaller particles, called protons, neutrons and electrons. The protons and neutrons are in the middle of the atom. They are called the nucleus. The nucleus is surrounded by a cloud of electrons with a negative charge which are bound to the nucleus by an electromagnetic force.
Protons and neutrons are made up of even smaller particles called quarks. Electrons are elementary or fundamental particles; they cannot be split into smaller parts.
The number of protons, neutrons and electrons an atom has determines what element it is. Hydrogen, for example, has one proton, no neutrons and one electron; the element sulfur has 16 protons, 16 neutrons and 16 electrons.
Atoms move faster when in gas form (as they are free to move) than liquid and solid matter. In solid materials the atoms are tightly next to each other so they vibrate, but are not able to move (there is no room) as atoms in liquids do.

History

The word "atom" comes from the Greek ἀτόμος, indivisible, from ἀ-, not, and τόμος, a cut. The first historical mention of the word atom came from works by the Greek philosopher Democritus, around 400 BC.[3] Atomic theory stayed as a mostly philosophical subject, with not much actual scientific investigation or study, until the development of chemistry in the 1600s.
In 1777 French chemist Antoine Lavoisier defined the term element for the first time. He said that an element was any basic substance that could not be broken down into other substances by the methods of chemistry. Any substance that could be broken down was a compound.[4]
In 1803, English philosopher John Dalton suggested that elements were tiny, solid spheres made of atoms. Dalton believed that all atoms of the same element have the same mass. He said that compounds are formed when atoms of more than one element combine. According to Dalton, in a compound, atoms of different elements always combine the same way.
In 1827, British scientist Robert Brown looked at pollen grains in water and used Dalton's atomic theory to describe patterns in the way they moved. This was called Brownian Motion. In 1905 Albert Einstein used mathematics to prove that the seemingly random movements were down to the reactions of atoms, and by doing so he conclusively proved the existence of the atom.[5] In 1869 scientist Dmitri Mendeleev published the first version of the periodic table. The periodic table groups atoms by their atomic number (how many protons they have. This is usually the same as the number of electrons). Elements in the same column, or period, usually have similar properties. For example helium, neon, argon, krypton and xenon are all in the same column and have very similar properties. All these elements are gases that have no colour and no smell. Together they are known as the noble gases.[4]
The physicist J.J. Thomson was the first man to discover electrons. This happened while he was working with cathode rays in 1897. He realized they had a negative charge, unlike protons (positive) and neutrons (no charge). Thomson created the plum pudding model, which stated that an atom was like plum pudding: the dried fruit (electrons) were stuck in a mass of pudding (protons). In 1909, a scientist named Ernest Rutherford used the Geiger–Marsden experiment to prove that most of an atom is in a very small space called the atomic nucleus. Rutherford took a photo plate and surrounded it with gold foil, and then shot alpha particles at it. Many of the particles went through the gold foil, which proved that atoms are mostly empty space. Electrons are so small they make up only 1% of an atom's mass.[6]
Ernest Rutherford in 1910, shortly before he won the Nobel Prize for physics.
In 1913, Niels Bohr introduced the Bohr model. This model showed that electrons orbit the nucleus in fixed circular orbits. This was more accurate than the Rutherford model. However, it was still not completely right. Improvements to the Bohr model have been made since it was first introduced.
In 1925, chemist Frederick Soddy found that some elements in the periodic table had more than one kind of atom.[7] For example any atom with 2 protons should be a helium atom. Usually, a helium nucleus also contains two neutrons. However, some helium atoms have only one neutron. This means they are still helium, as the element is defined by the number of protons, but they are not normal helium either. Soddy called an atom like this, with a different number of neutrons, an isotope. To get the name of the isotope we look at how many protons and neutrons it has in its nucleus and add this to the name of the element. So a helium atom with two protons and one neutron is called helium-3, and a carbon atom with six protons and six neutrons is called carbon-12. However, when he developed his theory Soddy could not be certain neutrons actually existed. To prove they were real, physicist James Chadwick and a team of others created the mass spectrometer.[8] The mass spectrometer actually measures the mass and weight of individual atoms. By doing this Chadwick proved that to account for all the weight of the atom, neutrons must exist.
In 1937, German chemist Otto Hahn became the first person to create nuclear fission in a laboratory. He discovered this by chance when he was shooting neutrons at a uranium atom, hoping to create a new isotope.[9] However, he noticed that instead of a new isotope the uranium simply changed into a barium atom. This was the world's first recorded nuclear fission reaction. This discovery eventually led to the creation of the atomic bomb.
Further into the 20th century physicists went deeper into the mysteries of the atom. Using particle accelerators they discovered that protons and neutrons were actually made of other particles, called quarks.
The most accurate model so far comes from the Schrödinger equation. Schrödinger realized that the electrons exist in a cloud around the nucleus, called the electron cloud. In the electron cloud, it is impossible to know exactly where electrons are. The Schrödinger equation is used to find out where an electron is likely to be. This area is called the electron's orbital.

Structure and parts

Parts

The complex atom is made up of three main particles; the proton, the neutron and the electron. The isotope of Hydrogen Hydrogen-1 has no neutrons, and a positive hydrogen ion has no electrons. These are the only known exceptions, all other atoms have at least one proton, neutron and electron each.
Electrons are by far the smallest of the three, their mass and size is too small to be measured using current technology.[10] They have a negative charge. Protons and neutrons are of similar size to each other[10] Protons are positively charged and neutrons have no charge. Most atoms have a neutral charge; because the number of protons (positive) and electrons (negative) are the same, the charges balance out to zero. However in ions (different number of electrons) this is not always the case and they can have a positive or a negative charge. Protons and Neutrons are made out of quarks, of two types; up quarks and down quarks. A proton is made of two up quarks and one down quark and a neutron is made of two down quarks and one up quark.

Nucleus

The nucleus is in the middle of an atom. It is made up of protons and neutrons. Usually in nature, two things with the same charge repel or shoot away from each other. So for a long time it was a mystery to scientists how the positively charged protons in the nucleus stayed together. They solved this by finding a particle called a Gluon. Its name comes from the word glue as Gluons act like atomic glue, sticking the protons together using the strong nuclear force. It is this force which also holds the quarks together that make up the protons and neutrons.
A diagram showing the main difficulty in nuclear fusion, the fact that protons, which have positive charges, repel each other when forced together.
The number of neutrons in relation to protons defines whether the nucleus is stable or goes through radioactive decay. When there are too many neutrons or protons, the atom tries to make the numbers the same by getting rid of the extra particles. It does this by emitting radiation in the form of alpha, beta or gamma decay.[11] Nuclei can change through other means too. Nuclear fission is when the Nucleus splits into two smaller nuclei, releasing a lot of stored energy. This release energy is what makes nuclear fission useful for making bombs and electricity, in the form of nuclear power. The other way nuclei can change is through nuclear fusion, when two nuclei join together, or fuse, to make a heavier nucleus. This process requires extreme amounts of energy in order to overcome the electrostatic repulsion between the protons, as they have the same charge. Such high energies are most common in stars like our Sun, which fuses hydrogen for fuel.

Electrons

Electrons orbit or go around the nucleus. They are called the atom's electron cloud. They are attracted towards the nucleus because of the electromagnetic force. Electrons have a negative charge and the nucleus always has a positive charge, so they attract each other. Around the nucleus some electrons are further out than others. These are called electron shells. In most atoms the first shell has two electrons, and all after that have eight. Exceptions are rare, but they do happen and are difficult to predict.[12] The further away the electron is from the nucleus, the weaker the pull of the nucleus on it. This is why bigger atoms, with more electrons, react more easily with other atoms. The electromagnetism of the nucleus is not enough to hold onto their electrons and they lose them to the strong attraction of smaller atoms. [13]

Radioactive decay

Some elements, and many isotopes, have what is called an unstable nucleus. This means the nucleus is either too big to hold itself together[14] or has too many protons, electrons or neutrons. When this happens the nucleus has to get rid of the excess mass or particles. It does this through radiation. An atom that does this can be called radioactive. Unstable atoms continue to be radioactive until they lose enough mass/particles that they become stable. All atoms above atomic number 82 (82 protons) are radioactive.[14]
There are three main types of radioactive decay; alpha, beta and gamma.[15]
  • Alpha decay is when the atom shoots out a particle having two protons and two neutrons. This is essentially a helium nucleus. The result is an element with atomic number two less than before. So for example if a beryllium atom (atomic number 4) went through alpha decay it would become helium (atomic number 2). Alpha decay happens when an atom is too big and needs to get rid of some mass.
  • Beta decay is when a neutron turns into a proton or a proton turns into a neutron. In the first case the atom shoots out an electron, in the second case it is a positron (like an electron but with a positive charge). The end result is an element with one higher or one lower atomic number than before. Beta decay happens when an atom has either too many protons, or too many neutrons.
  • Gamma decay is when an atom shoots out a gamma ray, or wave. It happens when there is a change in the energy of the nucleus. This is usually after a nucleus has already gone through alpha or beta decay. There is no change in the mass, or atomic number or the atom, only in the stored energy inside the nucleus.
Every radioactive element or isotope has something called a half life. This is how long it takes half of any sample of atoms of that type to decay until they become a different stable isotope or element.[16] Large atoms, or isotopes with a big difference between the number of protons and neutrons will therefore have a long half life.

References

Other websites