Take a look at the picture attached. This is the ordered arrangement of writing an electronic configuration. Each s orbital holds 2 electrons, p holds 6, d holds 10 and f holds 14. They are presented as exponents. You can move on to the next orbital as long as the previous one is fully occupied.
Si: This has 14 electrons. So, you would write the electronic configuration as: 1s²2s²2p⁶3s²3p² (such that the exponents add up to 14).
Ga: This has 31 electrons. So, you would write the electronic configuration as: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹ (such that the exponents add up to 31).
As: This has 33 electrons. So, you would write the electronic configuration as: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p³ (such that the exponents add up to 33).
Ge: This has 32 electrons. So, you would write the electronic configuration as: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p² (such that the exponents add up to 32).
Al: This has 13 electrons. So, you would write the electronic configuration as: 1s²2s²2p⁶3s²3p¹ (such that the exponents add up to 13).
Cd: This has 48 electrons. So, you would write the electronic configuration as: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s² (such that the exponents add up to 48).
S: This has 16 electrons. So, you would write the electronic configuration as: 1s²2s²2p⁶3s²3p⁴ (such that the exponents add up to 16).
Se: This has 34 electrons. So, you would write the electronic configuration as: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁴ (such that the exponents add up to 34).
