Elements

Q.

Define the term element?

Q.

Which among the following is the most abundant element in the Earth's crust?

1. Carbon dioxide

2. Nitrogen

3. Oxygen

4. Carbon monoxide

Q. Germanium is a metalloid. Is this statement true or false?

1. False
2. True

Q.

Which of the following is true?

1. $\mathrm{a}\in \left\{\left\{\mathrm{a}\right\},\mathrm{b}\right\}$

2. $\left\{\mathrm{b},\mathrm{c}\right\}\in \left\{\mathrm{a},\left\{\mathrm{b},\mathrm{c}\right\}\right\}$

3. $\left\{\mathrm{a},\mathrm{b}\right\}\in \left\{\mathrm{a},\left\{\mathrm{b},\mathrm{c}\right\}\right\}$

4. None of these

Q. Brass and bronze are:

1. Elements
2. Compounds
3. Mixtures
4. All of the above

Q. Give two examples for each of the following:​

(d) Elements which are liquids​

Q.

Which of these an irreversible change

1. burning of a matchstick

2. inflating tyres

3. lighting a bulb

4. inflating a balloon

Q.

Choose the odd one out.

1. Mercury

2. Copper

3. Iron

4. Methane

Q.

Statement B: Cooling a metal can also bring about change in its shape.

1. Both statements are correct

2. Statement A is true; Statement B is false

3. Statement A is false; Statement B is true

4. Both the statements are false

Q.

Tearing of paper is said to be a change that cannot be reversed. What about paper recycling?

Q. Let 'X' be a type of change that falls under the category of both physical and reversible change. Which among the following processes could 'X' be?

1. Rusting of iron
2. Burning of wood
3. Melting of wax
4. Curdling of milk

Q. Digestion of food is a/an _______ change.

1. temporary
2. reversible
3. non-desirable
4. irreversible

Q.

Hydrogen is the most abundant element in the earths crust.

1. True
2. False

Q.

4. Describe an irreversible change that you can bring about by heating.

Q.

Which among the following is a mixture?

1. Oxygen

2. Air

3. Water

4. Sugar

Q.

Elements are substances formed by chemical combination of two or more types of atoms.

1. True
2. False

Q. Which of the following is most abundant element in the earth crust?

1. Nitrogen
2. Oxygen
3. Hydrogen
4. Argon

Q.

Which of the following element is liquid at room temperature?

1. Carbon

2. Nitrogen

3. Sodium

4. Bromine

Q.

(a) Solids	(i) Can flow in all direction
(b) Sublimation	(ii) The temperature at which a liquid changes into its gaseous state
(c) Boiling point	(iii)Can have any number of free surfaces.
(d) Gases	(iv)Gaps between particles
(e)Intermolecular space	(v)Change of state directly from solid to gas.

Q.

Define the term element.

Q. should we study the electronic configuration of exceptional elements other than chromium and copper?? like palladium, silver etc?

Q.

How are elements different from compounds?

Q.

H₂ is an element.

1. True
2. False

Q.

What will be the atomicity of:

a) The molecule which we consume during respiration and released during photosynthesis.

b) The red coloured element which we use in matchboxes.

c) The pale blue gas which forms a layer that absorbs sun's UV radiation.

1. 2, 4, 2 respectively

2. 4, 2, 2 respectively

3. 2, 3, 4 respectively

4. 2, 4, 3 respectively

Q.

2. Can you get burnt paper back to its original form?

Q. Which of the following is not a pure substance?

1. Sugar solution
2. Oxygen
3. Hydrogen
4. Copper

Q. A sheet of paper is used to make a paper boat. Identify the changes involved in this.

1. Permanent
2. Temporary
3. Natural
4. Man-made

Q.

What will happen to most of the matter that is heated?

1. It expands

2. It contracts

3. It remains the same

4. It changes color

Q.

Which of the following statement is true?

1. False

2. Can't say

3. Insufficient data

4. True

Q.

5. (b) Amongst all the elements discovered, how many are:

(ii) Non-metals