Question

An element X has 19 electrons in it's ground state. Which group and period does this element belong to?

• A. 2nd group & 3rd period
• B. 2nd group & 4th period
• C. 3rd group & 4th period
• D. 2nd group & 2nd period

Answer 1

The correct option is B

2nd group & 4th period

The element X belongs 4th period and 2nd group.

The element X electronic distribution is 2 8 8 2

Hence, the group this element belongs to is 2nd and the period is 4th.

We can calculate these two values by counting the clouds (give us the period number) and valence shell electron number (give us the group number)