Electrons And The Periodic Table Worksheet printable pdf download

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Skill Sheet 18-B

Electrons and the Periodic Table

What do electrons have to do with the periodic table? In this skill sheet, you will learn how

electrons are organized in the energy levels that orbit the nucleus of an atom. You will also

discover the relationship between electrons and the organization of the periodic table.

1. How do you describe the location of an electron?

As you have learned, electrons “live” in one of the seven

energy levels surrounding the nucleus of the atom.

Generally speaking, the farther away from the nucleus

the energy level, the greater the amount of energy

required for an electron to occupy that level. Electrons

tend to fill in the first energy level first, the second energy

level second, and so on, because they fill the levels from

lowest to highest energy, that is, from first to outermost.

Energy levels are divided into smaller regions called

orbitals. Each orbital designates a specific region of the

energy level where an electron exists. The different

orbitals are designated by the letters s, p, d, and f.

Electrons fill the energy levels and orbitals in a certain order. The position that

has the lowest energy is filled first. The position that has the lowest energy is in

the first energy level (the level closest to the nucleus), in the s orbital. This

electron’s position is represented by writing: 1s

The order in which electrons fill all seven energy levels (1-7) and all electron

orbitals (s, p, d, and f) is shown below. This order (going from left to right) is

called an electron configuration.

Electron configuration for ununoctium

Lowest

→

Highest

energy

Each element on the periodic table has a unique electron configuration, based on its atomic

number This number tells you the number of electrons in a neutral atom of the element. For

example, hydrogen’s electron configuration is 1s

and carbon’s electron configuration is 1s

The electron configuration above (which includes all the energy levels and orbitals on the periodic

table) is for ununoctium (Uuo), the very last element on the periodic table.

In the fourth, fifth, sixth, and seventh energy levels, you will notice orbitals with numbers from a

lower energy level. For example, the 4s and 4p orbitals and the 3d orbital are all in the fourth

energy level. This is because the energy level of the 3d electrons overlaps with the energy levels

for electrons in the fourth energy level. Also, the 4s orbital is filled before the 3d orbital. This is

because the 4s orbital has a lower energy than the 3d orbital. To complicate matters, electrons fill

the d and f orbitals in irregular patterns.

Electrons And The Periodic Table Worksheet