# Multiplication and Division

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

Chromium’s atomic number = 24.

Double of Chromium = 24 × 2
= 48
Therefore, Cadmium (Cd) has the double atomic number of Chromium.

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

Mercury’s atomic number = 80.
Half of Mercury = 80 ÷ 2
= 40
Therefore, Zirconium (Zr) has half of Mercury’s atomic number.

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

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

BODMAS Rule

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

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).

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

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).