Question

When an atom of lithium loses an electron, the atom becomes a

(1) negative ion with a radius smaller than the radius of the atom
(2) negative ion with a radius larger than the radius of the atom
(3) positive ion with a radius smaller than the radius of the atom
(4) positive ion with a radius larger than the radius of the atom

Answer 1

Because lithium is losing an electron, it will consequently have one more proton than electron, making it positive (rule out 1 and 2). A cation is always smaller than its neutral atom, so 3 is your answer.

Answer 2

Answer: When a lithium atom looses an electron, the atom becomes a positive ion with a radius smaller than the radius of the atom

Step-by-step explanation:

Lithium is the 3rd element of the periodic table having electronic configuration of
`1s^22s^1`.

This element will loose 1 electron to form
`Li^+` (positive) ion.

There are two types of ions:

• Cations: They are formed when an atom looses its valence electrons. They are positive ions.
• Anions: They are formed when an atom gain electrons in its outermost shell. They are negative ions.

For positive ions, the removal of electron increases the nuclear charge for an outermost electron because the outermost electrons are more strongly attracted by the nucleus that have same number of protons. So, the effective nuclear charge increases for cations. This results in the shrinkage of atom and thus decrease in the radius of atom is observed.

Hence, when a lithium atom looses an electron, the atom becomes a positive ion with a radius smaller than the radius of the atom