Question

A sodium cation different number of electrons from
1.F-
2.O2-
3.Al3+
4.Li+

Answer 1

sorry what did you ask

Answer 2

Answer:  $Li^{+}$

Explanation:

Isoelectronic specie are defined as the molecules which have the same number of electrons.

$Na^+$:

Atomic number of sodium is 11 and thus has 11 electrons.$Na^{+}$ is formed by loss of 1 electrons and thus has 10 electrons.

1. Atomic number of fluorine is 9 and thus has 9 electrons.$F^{-}$ is formed by gain of 1 electron and thus has 10 electrons.

2. Atomic number of oxygen is 8 and thus has 8 electrons. $O^{2-}$  is formed by gain of 2 electrons and thus has 10 electrons.

3. Atomic number of aluminium is 13 and thus has 13 electrons.$Al{^3+}$ is formed by loss of 3 electrons and thus has 10 electrons.

4. Atomic number of lithium is 3 and thus has 3 electrons. $Li^{+}$ is formed by loss of 1 electron and thus has 2 electrons .