4.1.2 Modern Periodic Table

1. In the modern periodic table, the elements are arranged in ascending order of proton number.
2. The vertical columns of the periodic table are called GROUPs whereas the horizontal rows are called the PERIODs.

Group

1. The vertical columns of the periodic table are called Group.
2. There are 18 groups in the periodic table.
3. All the elements in the same group have the same number of valence electron.
4. Thus, elements in the same group exhibit similar chemical properties.
5. The Group is named according to their position in the periodic table. For example, the first group is called Group 1, the second group is called Group 2 and so on.
6. Group 3 to Group 12 are categorised to another big group, called the Transition Metal Group.
7. Group 1, 2, 17 and 18 have a trivial name, as shown in the table below.

Period

1. The horizontal rows are called the PERIOD.
2. There are 7 periods in the period table.
3. The first period only has 2 elements only.
4. The second and third period consists of 8 elements, are called the short period.
5. The fourth and the fifth period consist of 18 elements, are called the long period.
6. The sixth and seventh period has 32 elements.