Question

Explain the following:

Atoms combine by transfer and sharing of electron(s)

Answer 1

Atoms are combined with other atoms to achieve noble gas configuration.

• Noble gases are found to be stable because of the octet rule.
• The octet rule states that the atoms that have 8 electrons in their outermost shell are stable.
• Atoms try to achieve this by the complete transfer of electrons (loss or gain) or sharing of electrons.

Combination by transfer of electrons:

Example of formation of a sodium cation (Na⁺)

• The electronic configuration of sodium (Na) is 2, 8, 1 and it is unstable. It tries to achieve stability by losing one electron and attaining the noble gas configuration of neon i.e.; 2, 8. The sodium-ion thus formed combines with an oppositely charged ion to form an ionic compound.

Combination by sharing of electrons:

Example of formation of Hydrogen (H₂) molecule

• As a hydrogen atom contains 1 electron in its valence shell, it is unstable.
• It tries to achieve stability by completing its duplet of electrons by sharing electrons with another hydrogen atom by forming a covalent bond, a bond formed due to the sharing of electrons between atoms.
• Through sharing, both the hydrogen atoms of the hydrogen molecule complete their duplet and attains stability according to the duplet rule.