CIE Chemistry (US-0439): Specimen Questions with Answers 171 - 172 of 240

Question number: 171

MCQ▾

Question

Which of the following is not true about the modern periodic table?

Choices

Choice (4) Response

a.

It gives information about the electronic configuration of the elements.

b.

It cannot accommodate the isotopes.

c.

It is based on the increasing atomic number of elements.

d.

None of the above

Answer

c.

Explanation

Since the modern periodic table is based on the increasing atomic number and not atomic mass, therefore the problem of Mendeleev’s periodic table regarding accommodation of the isotopes was solved. No matter whatever the atomic mass is, the atomic number stays the same for all the isotopes of a particular element. Hence isotopes are accommodated in the modern periodic table.

Question number: 172

MCQ▾

Question

The organic compound Methyne is not possible because:

Choices

Choice (4) Response

a.

It is very difficult to extract methyne from the ores.

b.

Methyne is highly unstable.

c.

Methyne is highly poisonous.

d.

Methyne has 1 carbon atom.

Answer

d.

Explanation

  • Methyne has the prefix ‘Meth’ which means that the compound has carbon atom. “yne” suffix is used for alkyne family. An alkyne has carbon-carbon triple covalent bond.

  • So atleast carbon atoms are required for carbon-carbon triple covalent bond. But methyne has only carbon atom.

  • Hence triple bond between carbon atoms is not possible. Thus methyne is not possible because methyne has carbon atom.