# **Periodic Table**

The periodic table arranges the chemical elements. Here students will learn about periodic table elements, periodic table groups, and periodic table atomic numbers that connect students with the mathematical concept BODMAS rule.

## What Is the Periodic Table?

An atom of an element consists of three parts, namely:

- Electron
- Proton
- Neutron

The proton’s number of any element equals the element’s atomic number. It is denoted by the letter “Z”.

The periodic table is an arrangement of all the chemical elements in increasing order of the atomic number of the elements and their chemical properties.

There are 118 elements in the modern periodic table.

The symbol is used to represent the elements in the periodic table. Each element has a unique symbol.

The number within each square represents the atomic number of the corresponding element.

## The Periodic Table of Elements:

A periodic table consists of the following:

- Period
- Group

**Period:**

The horizontal row of the periodic table is called the period.

There are seven periods in the periodic table.

## Periodic Table Groups:

The vertical column of the periodic table is called the group.

There are eighteen groups in the periodic table.

Apart from the periods and the groups, there are two rows outside the periodic table, which consist of the following:

- Lanthanides
- Actinides

## Where Is Atomic Number in Periodic Table:

Below is a periodic table section with the symbol and the atomic numbers of each element in each square.

**Multiplication and Division**

## Question 1:

Write the Name of the Element Whose Atomic Number Is Double the Atomic Number of the Element Chromium (Cr).

### Answer 1:

Chromium’s atomic number = 24.

Double of Chromium = 24 × 2

= 48

Therefore, Cadmium (Cd) has the double atomic number of Chromium.

## Question 2:

Write the Name of the Element Whose Atomic Number Is Half the Atomic Number of the Element Mercury (Hg).

### Answer 2:

Mercury’s atomic number = 80.

Half of Mercury = 80 ÷ 2

= 40

Therefore, Zirconium (Zr) has half of Mercury’s atomic number.

## Question 3:

Name Two Elements Such That the Sum of Their Atomic Number Is Equal to the Atomic Number of Copernicium.

### Answer 3:

The answer may vary.

The atomic number of Copernicium = 112.

The atomic number of Zirconium (Zr) = 40

The atomic number of Hafnium = 72

The sum of 40 and 72 is (40 + 72) = 112

Therefore, Copernicium’s atomic number equals the sum of the atomic numbers of Zirconium and Hafnium.

**BODMAS Rule**

## Question 4:

Solve the Expression 2 × 112 ÷ 4 + 19. Name the Element Whose Atomic Number Is Equal to the Answer Obtained.

### Answer 4:

From the BODMAS rule of arithmetic, it follows that to solve the given expression; we will follow the order:

- Divide
- Multiply
- Addition

First, divide 112 by 4.

Second, multiply two by 28

Third, add 56 and 19.

2 × 112 ÷ 4 + 19

= 2 × 28 + 19

= 56 + 19

= 75

The table shows that the element whose atomic number equals 75 is Rhenium (Re).

## Question 5:

Solve the Expression 2 × 112 ÷ 4 + 19. Name the Element Whose Atomic Number Is Equal to the Answer Obtained.

### Answer 5:

First, divide 75 by 5.

Second, subtract 15 from 112.

Third, add 97 and 10.

112 – 75 ÷ 5 + 10

= 112 – 15 + 10

= 97 + 10

= 107

The table shows that the element whose atomic number equals 107 is Bohrium (Bh).