Question

Element A,B and C have atomic numbers 9, 20, and 10 respectively. Write down the formula of the compound formed by two of the above elements.

Answer 1

• Element A: It has atomic number 9 which represents Fluorine. It is a non-metal.
• Element B: It has atomic number 20 which represents Calcium. It is a metal.
• Element C:It has atomic number 10 which represents Neon. It is a noble gas and thus a chemically inert elements.

Elements that form compound:

Since element C is chemically inert, it will not form any type of compound. Therefore, when a metal (loses an electron to form cation) and non-metal (gains an electron to form anion) combines to form a compound, they generally form an ionic compound.

Hence, the formula of the compound formed by A and B is B⁺A^-.