Lesson 1, Topic 1
In Progress

Use proton number and the simple structure of atoms to explain the basis of the Periodic Table (see section 9), with special reference to the elements of proton number 1 to 20

The columns of the periodic table represent the groups of the periodic table.

The rows of the periodic table represent the periods of the periodic table.

As we move across the periodic table (from left to right) atoms get less metallic. The metallic atoms are in groups 1, 2 and transition metals.

As we move across the periodic table (from left to right) atoms get smaller.

As we move down the periodic table (by group) atoms get larger.

This change in atomic size occurs due to the number of electrons around the outer most shell of the atom. As number of electrons in the outer most shell increases, the size of the atom decreases as there is a stronger pull between protons in the nucleus and electrons in the outer most shell.