Introduction

Q.

What is Chromium’s atomic weight?

Q.

The difference between ${\text{U}}^{235}$ and ${\text{U}}^{238}$ atom is that ${\text{U}}^{238}$ contains $3$ more

1. protons

2. protons and $3$ more electrons

3. neutrons and $3$ more electrons

4. neutrons

Q.

Why are aqueous solutions of an ionic compounds able to conduct electricity? [1 MARK]

Q.

Which of the following statement(s) are correct about the importance of soil?

1. The soil is essential for agriculture.

2. The soil supports the growth of plants.

3. The soil provides useful microorganisms for the plants.

4. The soil provides water and nutrients to the plants.

Q.

Isobars differ in ______.

1. No of Nucleons

2. Atomic no

3. Atomic mass

4. None of the above

Q.

The pencil lead contains ___.

Q.

How does H2+ O2 -> H2O

Q. An atom of phosphorus has the symbol ${}_{15}^{31}\text{P}$. How many protons, electrons and neutrons are present in an atom of phosphorus?

1. Protons-15, electrons-15, neutron-16
2. Protons-15, electrons-16, neutrons-16
3. Protons-16, electrons-16, neutrons-15
4. Protons-15, electrons-15, neutron-15

Q.

Isotopes have different _______ number, because their nuclei contain different number of ________.

Q. An element Y is made up of 15 electrons and 16 neutrons. Which of the following is the correct symbolic representation of the element?

1. ${}_{15}^{31}Y$
2. ${}_{31}^{15}Y$
3. ${}_{16}^{15}Y$
4. ${}_{15}^{16}Y$

Q. Burst the bubbles that contain properties of silk.

1. Dull
2. Smooth
3. Shiny
4. Rough
5. Strong
6. Fine
7. Soft
8. Weak

Q.

A pair of isobars will will always have same physical properties, do you agree?.Explain.

Q. Which of the following liquids has lowest boiling point?

1. Alcohol
2. Water
3. Ether
4. Milk

Q.

If the mass of a single atom of an element E is $\left(2.65\times {10}^{-23}\right)\mathrm{g}$, then find its atomic weight and identify the element.

Q. In hilly regions, erosion can be minimised by

1. Terracing
2. Ploughing effectively
3. Manuring
4. Strip cropping

Q. Examples of physical changes are given below.​
Identify which of the following is incorrectly matched based on reversibility.​

P	Slicing of apple	Reversible
Q	Folding a paper to make a paper boat	Reversible
R	Blooming of flower in spring season	Irreversible
S	Melting of butter	Irreversible

1. P and S
2. R and P
3. P and Q
4. Q and S

Q. At room temperature, liquid metal and liquid non-metals are :

1. $Hg$ and $I_2$
2. $Cs$ and $C{l}_2$
3. $Hg$ and $B{r}_2$
4. $Cd$ and $S$

Q. Volcanic eruption is an example of desirable change.

1. True
2. False

Q.

Argon – 40 and Calcium – 40 are the examples of:

1. Isobars

2. Isotopes

3. Noble gases

4. Allotropes

Q. Pentavalence in phosphorus is more stable when compared to that of nitrogen even though they belong to same group is due to :

1. reactivity of phosphorus
2. inert nature of nitrogen
3. hydrogen and sulphurous acid
4. large size of phosphorus atom

Q. The number of neutrons present in the element ${}_Z^A\text{X}$ is given by ________.

1. $\text{Z}$
2. $\text{Z + A}$
3. $\text{Z - A}$
4. $\text{A-Z}$

Q. Which of the following is a physical change?

1. Melting of wax
2. Ripening of fruit
3. Rusting of iron
4. Explosion of crackers