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WAEC Chemistry 2016 Paper

Question : 3

Total: 50

^9_4Be^{2+}

Solution:

Concept:

Electrons in an ion are found by subtracting the positive charge from the atomic number.

Explanation:

For

^9_4Be^{2+}

, the atomic number is

Z = 4

A neutral beryllium atom therefore has

4

electrons.

The

2+

charge means the atom has lost

2

electrons.

So, remaining electrons

= 4 - 2 = 2

Answer:

2

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