STUDENT SPACE · TOPIC 1

Position and electronic configuration

Use an element’s position to predict its electrons, ions and properties.

The essentials

Elements appear in order of increasing proton number. Rows are periods and columns are groups.
For the first 20 elements, the period gives the number of occupied electron shells.
Group I: +1 Group II: +2 Group III: +3

Try each question before opening its hint or answer. Use paper for calculations and diagrams.

An atom has configuration 2,6. Give its group and the charge of its common ion.

Need a hint for Question 1?

Count occupied shells to find the period.

Check Question 1

Group VI, charge −2.

Element Y has configuration 2,8,2. Give its period, group and common ion charge.

Need a hint for Question 2?

Count shells, then outer electrons; consider electron loss.

Check Question 2

Period 3, Group II, charge +2. Y loses its two outer electrons.

Explain why lithium and sodium react similarly.

Need a hint for Question 3?

Compare their outer-shell configurations.

Check Question 3

Both atoms have one outer-shell electron and form +1 ions in their compounds.

Use Lesson 1 in your worksheet for written practice. Your teacher will discuss those answers in class.