Question

What do elements in the groups 1A through 8A have in common? (Choose all that apply)

a
they all have the same number of valence electrons
b
they all will have the same oxidation states for the ions they form
c
they all have the same number of energy shells
d
they were all discovered around the same time
e
they all have similar properties

Answer 1

The elements in groups 1A through 8A of the periodic table share the following characteristics:

**a** they all have the same number of valence electrons - **True**
- Elements in the same group (or family) have the same number of valence electrons, which leads to similar chemical properties.

**b** they all will have the same oxidation states for the ions they form - **False**
- While elements in the same group often have similar oxidation states, the specific oxidation states can vary. For example, alkali metals (group 1A) typically have a +1 oxidation state, while halogens (group 7A) typically have a -1 oxidation state.

**c** they all have the same number of energy shells - **False**
- The number of energy shells (or principal energy levels) increases as you move down a group. For example, lithium has 2 energy shells, while cesium has 6.

**d** they were all discovered around the same time - **False**
- The discovery of these elements occurred over a wide range of time periods, from ancient times to the modern era.

**e** they all have similar properties - **True**
- Elements in the same group display similar chemical and physical properties due to their similar valence electron configurations.

So, the correct options are **a** and **e**.