Valence electron

******************************************Helium atom model
In chemistry, valence electrons are the electrons contained in the outermost, or valence, electron shell of an atom. Valence electrons are important in determining how an element reacts chemically with other elements: The fewer valence electrons an atom holds, the less stable it becomes and the more likely it is to react.

The number of valence electrons.

The number of valence electrons of an element is determined by its periodic table group (vertical column) in which the sup element is categorized.
The number of electrons in an atom's outermost valence shell governs its bonding behavior. Therefore, elements with the same number of valence electrons are grouped together in the periodic table of the elements. As a general rule, the fewer electrons in an atom's valence shell, the more reactive it is. Group 1 alkali metals are therefore very reactive, with lithium, sodium, and potassium being the most reactive of all metals.

Every atom is much more stable, or less reactive, with a full valence shell. This can be achieved one of two ways: an atom can either share electrons with neighboring atoms, a covalent bond, or it can remove electrons from other atoms, an ionic bond. Another form of ionic bonding involves an atom giving some of its electrons to another atom; this also works because it can end up with a full valence by giving up its entire outer shell. By moving electrons, the two atoms become linked. This is known as chemical bonding and serves to build atoms into molecules or ionic compounds. Five major types of bonds exist:
ionic bonds
covalent bonds
coordinate covalent bonds (also called dative covalent bonds)
hydrogen bonds
metallic bonds
The valence electrons are also responsible for determining the electrical conductivity nature of an element.

Choose the correct answer to complete the paraghraph

1. In chemistry, valence electrons are:
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2. Where are the electrons contained?
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3. How is the number of valence electrons of an element determined?
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4. The number of electrons in an atom's outer valence shell what does it govern?
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5. The fewer electrons in an atom's valence shell, makes it more?

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6. alkali metals are very reactive, but wich metals are the most?

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7. How is every atom more stable and less reactive?

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8. When an atom shares electrons it is called?

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9. When an atom removes electrons from other aotms it is called?

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10. When electrons are moved, two atoms become linked this is called?

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