4 條 科學 的問題 ( 英文 ) 急急急 !!!

1.
The easier an atom releases electrons from its outermost shell, the higher are the metallic properties of the element.

Going down a group of the Periodic Table, the atomic sizes are increasing. This makes the atoms release electrons from the outermost shells more readily because such electrons experience decreasing nuclear attractions.

Across a period of the Periodic Table (from left to right), the atoms of the elements have increasing numbers of electrons in the outermost shells. If the atom has more electrons in the outermost shell, it is more difficult for this atom to lose all the electrons in the outermost shell to obtain a stable electronic structure. Furthermore, the atomic sizes are decreasing when going across the period. The electrons in the outermost shells are thus bound by increasing nuclear attractions when going across the period.
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2.
The most abundant element in the Earth’s crust is oxygen (a non-metal), followed by silicon ( a metalloid), aluminium (a metal) and iron (a metal).
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3.
For neon (an element in Period 1), the atom has a doublet structure. It is stable.

For argon, krypton and xenon, each atom has an octet structure. They are stable.

Each oxygen atom has 6 electrons in the outermost shell. When two oxygen atoms are joined together to form an O=O molecule, each O atom has an octet structure (4 electrons in the double bond and 4 unbonded electrons) and becomes stable.

Each nitrogen atom has 5 electrons in the outermost shell. When two nitrogen atoms are joined together to form an N≡N molecule, each N atom has an octet structure (6 electrons in the triple bond and 2 unbonded electrons) and becomes stable.
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4.
A metal with small size has only 1, 2 or 3 electrons in the outermost shell. Since hydrogen has only 1 electrons in the outermost shell, it is put on the metal side of the Periodic Table.

1. a metal is defined as the ability to remove electron to form cation. since Fr (Francium) has the lowest electronegativity comparing with all other elements, it loses its electrons most redily.

2. silicon - non metal, aluminum - metalloid, calcium - metal and magnesium - metal

3. because the noble gases has completed the octet rule just by themselves because they have 8 valence electrons. simply explaining the octet rule is that the atom needs to have 8 electrns surrounding it. however, O2- is lacking of 2 electrons, which it only has 6 valence electrons, to fulfil the octet rule and N3- is lacking of 3 electrons, which it only has 5 valence electrons, to fulfil the octet rule. so they fulfil the octet rule by sharing the electrons forming ::O=O:: and :N≡N:

4. because the first valence shell of orbitals can only contain 2 electrons maximum. also, the periodic table is arranged in the order of increasing valence electrons (electrons responsible for bonding) and so it is under the group 1. however it is a non-metal because it forms covalent bonds and behave in a non-metal way.