Statement-1: An atom having a valency of two can combine with two other atoms, each having a valency of one.

Statement-2: The valency of carbon in carbon dioxide $(C O_{2})$ is two.

Only statement 1 is true.

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Only statement 2 is false.

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Both statements are false.

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Both statements are true.

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Solution

The correct option is A Only statement 1 is true.
The combining capacity of an element is known as its valency. So, an element having a valency of 2 can combine with two atoms of an element having a valency of 1.

The formula of carbon dioxide $(C O_{2})$ is written from a short-cut method as shown below.
Symbol: C O
$↘ ↙$
Valency: 4 2

From the above method, the formula obtained for carbon dioxide is $C_{2} O_{4}$ . This formula is simplified taking whole no. ratio of valencies and written as $C O_{2}$ . Hence, the valency of carbon is always 4.

So, the valency of an element cannot always be derived from its compounds.

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Similar questions

Statement-1: An atom of valency 2 can combine with 2 other atoms of valency 1.
Statement-2: The valency of an element is the measure of its combining power with other atoms, when it forms chemical compounds or molecules.

Q. Statement I: Two atoms of X combine with three atoms of Y to form

X_{2} Y_{3}

.

Statement II: From the chemical formula of the compound

X_{2} Y_{3}

, we can conclude that the valency of X is 2.

Statement 1: An atom of valency 2 can combine with 2 other atoms of valency 1.
Statement 2: To write the chemical formula, one must know the valency of the element.

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(k)

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.
Statement 2 : Equivalent thermal conductivity of two rods of same physical dimensions and having same thermal conductivity

(k)

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Statement-1: $N_{2}$ and $H_{2} O$ are both molecules.
Statement-2: A molecule can have only similar kind of atoms.

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Statement-1: An atom having a valency of two can combine with two other atoms, each having a valency of one. Statement-2: The valency of carbon in carbon dioxide (CO2) is two.

Statement-1: An atom having a valency of two can combine with two other atoms, each having a valency of one.

Statement-2: The valency of carbon in carbon dioxide $(C O_{2})$ is two.