CIE Chemistry (US-0439): Specimen Questions with Answers 237 - 238 of 240

Question number: 237

MCQ▾

Question

While moving down a group in the modern periodic table, the size of an atom of an element ________.

Choices

Choice (4) Response

a.

Increases

b.

Decreases

c.

Partially increases

d.

None of the above

Answer

a.

Explanation

While moving down a group in the modern periodic table, number of electronic shells of the atoms of the elements increases as a result of which size of the atom increases.

Let us consider group 1 as an example.

Image of atom increases

Image of Atom Increases

Image of atom increases

It can be observed that while moving down the group, number of electronic shells increases gradually. As the number of shells increases so the size of the atom increases.

Similarly it can be observed in all other groups that the number of shells increases gradually while moving down the group. So the size of the atom increases while moving down a group.

Question number: 238

Short Answer Question▾

Write in Short

Describe a test for iodide ions

test ……………………………………………………………………………………………………………. .

result ……………………………………………………………………………………………………. .

Explanation

You can test to see if a solution contains iodide ions by using silver nitrate. If silver nitrate solution is added to a sample of water containing iodine ions the silver halide is precipitated. This is because the silver halides are all insoluble in water.

Image of iodide ions

Image of Iodide Ions

Image of iodide ions