Elements

Q.

Why are metals good conductors of electricity?

Q.

Which is the most ductile metal known?

1. Silver

2. Platinum

3. Gold

4. Copper

Q.

What are some examples of amphoteric oxides?

Q. The mnemonic code for remember the elements of group 1, 2, 13, 14, 15, 16, 17 and 18.And that for the period 4, 5, 6 and 7 for d block elements.

Q.

Is Zinc oxide acidic or basic?

Q.

Classify the following substance as element, compound or mixture:

Oxygen

Q.

Aluminium oxide reacts with sulphuric acid to form :

1. Aluminium sulphate and hydrogen

2. Aluminium sulphate and oxygen

3. Aluminium sulphate and water

4. Aluminium sulphate and sulphur oxide

Q. Question 3.1

Write a balanced chemical equation with state symbols for the reaction:

The solution of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.

Q. In the decomposition of lead (II) nitrate to give lead (II) oxide, nitrogen dioxide and oxygen gas, the coefficient of nitrogen dioxide (in the balanced equation) is:
(All coefficients being natural numbers)

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

Q.

Magnesium is a non-combustible metal. (True / False). Also write the false statements in their correct form.

1. True
2. False

Q.

Classify the following as element, mixture or compound:

ice

Q.

A substance that contains only one kind of atom is _____(an element/a mixture).

Q.

Classify the following as element, mixture or compound:

18-carat gold

Q. _______ is an alloy of copper and tin.

1. Gold
2. Bronze
3. Steel
4. Brass

Q.

Compound is the simplest form of matter.

1. True
2. False

Q. Question 6.3
Balance the following chemical equation:

$\text{NaCl}+{\text{AgNO}}_3\to \text{AgCl}+{\text{NaNO}}_3$

Q.

Name a metal that burns in air with a dazzling white light.

Q. Which of the following reacts with oxygen on strong heating but not with water?

1. Magnesium
2. Copper
3. Gold
4. Sodium

Q.

Define element

Q.

23. ___________ burns in oxygen with a brilliant golden yellow flame.

1. $\mathrm{Na}$

2. $\mathrm{Ca}$

3. $\mathrm{Mg}$

4. $\mathrm{K}$

Q. Question 5.1
Translate the following statement into chemical equation and then balance it:

Hydrogen gas combines with nitrogen to form ammonia.

Q.

Classify the following substance as element, compound or mixture:

Iron

Q. What is gram atomic mass? Give three examples.

Q.

If oxygen atom gains 2 electrons, write the symbol, number of protons and number of electrons of the newly formed ion.

Q. The balanced chemical equation for potassium reacting with water is:

1. $\text{K}\text{(s)}+2{\text{H}}_2\text{O(l)}\to \text{KOH(aq)}+{\text{H}}_2\text{(g)}$
2. $2\text{K}\text{(s)}+{\text{H}}_2\text{O(l)}\to 2\text{KOH(aq)}+{\text{H}}_2\text{(g)}$
3. $\text{K}\text{(s)}+{\text{H}}_2\text{O}\text{(l)}\to \text{KOH(aq)}+{\text{H}}_2\text{(g)}$
4. $2\text{K}\text{(s)}+2{\text{H}}_2\text{O}\text{(l)}\to 2\text{KOH(aq)}+{\text{H}}_2\text{(g)}$

Q.

Classify the following substance into elements, compounds and mixtures:

Marble

Q.

Which of the following is an example of an amphoteric oxide?

1. ${\mathrm{SO}}_2$

2. ${\mathrm{P}}_2{\mathrm{O}}_5$

3. $\mathrm{BaO}$

4. $\mathrm{ZnO}$

Q. Question 26
Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among the following alloys contain non-metal as one of its constituents?
(a) Brass
(b) Bronze
(c) Amalgam
(d) Steel

Q.

77. Identify the following as element or compound.

Au

Q.

Fill in the blanks :
__________ is a pure substance which is made up of only one kind of atoms.