Question

write the chemical symbols for three different atoms or atomic cations with 12 electrons.

Explanation:

Step1: Recall neutral atom with 12 electrons

The atomic number of an element is equal to the number of protons and in a neutral atom, the number of electrons is equal to the number of protons. The element with atomic number 12 is magnesium, and its chemical symbol is Mg.

Step2: Consider cations with 12 electrons

A calcium - 2+ ion (Ca²⁺) has atomic number 20 (20 protons). When it loses 2 electrons, it has 20 - 2=18 - 2 = 12 electrons.

Step3: Consider another cation

A scandium - 3+ ion (Sc³⁺) has atomic number 21 (21 protons). When it loses 3 electrons, it has 21 - 3=18 electrons in its neutral state - 3=12 electrons.

Answer:

Mg, Ca²⁺, Sc³⁺