Valency

Q.

Define valency. Give valency to copper and iron?

Q. Find the molecular mass of carbon dioxide (CO2) in a.m.u.

1. 44

Q.

What is the valency of Iodine?

Q.

Question 11
Which one of the following elements exhibit maximum number of valence electrons?

(a) Na
(b) Al
(c) Si
(d) P

Q.

The valency of Nitrogen in the following is?

NO, NO2, N2O3

Q.

The chemical formula of aluminium sulphate is

1. AlSO₄

2. Al(SO₄)₂

3. Al₂(SO₄)₃

4. Al₃(SO₄)₂

Q.

Find the chemical formula of carbon tetrachloride. [3 MARKS]

Q. What is the valency of carbonate ion (${\text{CO}}_3^{2-}$)?

1. 2
2. 3
3. 4
4. 1

Q.

Which one of the following is a strong electrolyte?

1. Carbon disulfide

2. Ammonium hydroxide

3. Sodium chloride

4. Water

Q.

Valency of Calcium element is:

1. 2

2. 3

3. 4

4. 5

Q.

A organic compound having carbon, hydrogen, oxygen and nitrogen was found to contain $\mathrm{C}=41.37\%,\mathrm{H}=5.75\%,\mathrm{O}=36.8\%$ and the rest nitrogen. If the vapor density of the compound is $43.3$, calculate the molecular formula of the compound.

Q.

What is the valency of :

(a) fluorine in $Ca{F}_2$ (b) sulphur in $S{F}_6$

(c) phosphorus in $P{H}_3$ (d) carbon in $C{H}_4$

Q.

The total number of electrons in a nitrogen atom is 7. Find the number of valence electrons in it.

Q.

Chemical formula of a compound is A₂B₃. The valency of A is _______ .

1. 5

2. 3

3. 2

4. 4

Q.

What is the mass of one atom of calcium?

Q.

The number of valence electrons in a sulphide ion, $S^{2-}$, is :

(a) 16

(b) 10

(c) 9

(d) 8

Q. The formula of a metal oxide is $M_2{O}_3$. If the metal forms its chloride, what will the formula of that compound be?

1. $M_{2}Cl$
2. $M_{3}Cl$
3. $MC{l}_3$
4. $MC{l}_2$

Q.

Why iron has two valencies?

Q.

Name or state the following :

(a) An element having valency zero.

(b) Metal with valency one.

(c) Atoms of the same element differing in mass numbers.

(d) Elements having same mass number but different atomic number.

(e) Bond formed by transfer of electron(s).

(f) Ion formed by gain of electron(s).

Q.

Consider an atom of iron represented as${}_{26}{}^{}\mathrm{Fe}^{56}$. Give the number of protons, electrons, and neutrons present in the atom.

Q.

How many valence electrons are present in a Potassium atom?

Q.

The combining capacity of an element is known as its ______________.

1. atomicity

2. configuration

3. valency

4. velocity

Q. Question 1 (i)
Write down the formulae of:
(i) Sodium oxide

Q.

Give the formaula and valency of :

(a) aluminate ........................ ..............................

(b) chromate ........................ ................................

(c) aluminium .......................... ................................

(d) cupric ................................. ...................................

Q. The number of valence electrons in a lithium atom is:

1. 3
2. 2
3. 1
4. 4

Q.

Write the formula and valency of the Chromate ion.

Q.

(a) Explain the terms 'valency' and 'variable valency'.

(b) How are the elements with variable valency named ? Explain with an example.

Q.

If the formula of the nitride of a metal X is XN, what is the formula of:

Its sulphate.

Q.

Which noble gas has less than 8 electrons in the valence shell of its atom? What is this number?

Q.

What is the valency of carbon in ${CH}_4$ ?

__