Determine the valence electron/s and predict the period and group number of the following elements by electron configuration. Provide evidence by showing work properly. Use a sheet of paper to do your work. 1. Silicon 2. Xenon 3. Barium 4. Potassium 5. Iodine

The location of an element can be estimated from its electron configuration

We can divide the periodic system into several parts:

1. Block s: groups 1 and 2 (having a configuration of 1s-7s) consist of active metals except for H (non-metals) and He (noble gases)

2. Block p: group 13-18 (has a 2p-6p configuration), also called a representative element because it includes metals, non-metals and metalloids

3. Block d: group 3-12 (having the 3d-6d configuration), are transition metal elements

4. Block f: Lanthanides and Actinides (having a 4f-5f configuration), are inner transition elements that are also metal

group⇒valence electron

period⇒the greatest value of the quantum number n

1. Silicon

electron configuration : [Ne] 3s²3p²

valence electron = 4(2+2), block p : group 14

period = n = 3

2. Xenon

electron configuration : [Kr] 4d¹⁰5s²5p⁶

valence electron = 8(2=6),block p :  group 18

period = n = 5

3. Barium

electron configuration : [Xe] 6s²

valence electron = 2, block s, group 2

period = n = 6

4. Potassium

electron configuration : [Ar] 4s¹

valence electron = 1, block s, group 1

period = n = 4

5. Iodine

electron configuration : [Kr] 4d¹⁰5s²5p⁵

valence electron = 7(2+5), block p, group 17

period = n = 5