The atom of an element has $9$ protons, $9$ electrons and $10$ neutrons.

What is the atomic number of the element?

The atom of an element has 9 protons, 9 electrons and 10 neutrons.

Predict the valency of the element.

The electronic configuration of elements is given.

Name the elements. $2, 8, 5$.

The electronic configuration of elements is given. Name the elements.

$2, 8, 8, 2$

The electronic configuration of elements is given. Name the elements.

$2, 8, 1$

An atom $\mathrm{X}$has $4$ protons and $5$ neutrons with electronic configuration $2, 2$.

Give information about its atomic number.

An atom $\mathrm{X}$ has $4$ protons and $5$  neutrons with electronic configuration $2, 2$.

Give information about its mass number.