Introduction

Q. in hydrogen atom the de broglie wavelength of an electron in the second bohr orbit is

Q. Question 7(a)
What is the mass of:
(a) 1 mole of nitrogen atoms?

Q.

Write any four properties of material.

Q.

The atomic weight of calcium is _______.

Q.

What are the five elements of our environment?

Q. What is the chemical name of the element with symbol ‘P’?

1. Potassium
2. Phosphorous
3. Platinum
4. Plumbum

Q. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> What are valence electrons? How many valence electrons does a magnesium atom have?

Q.

Symbol of an element represents:

1. One molecule of the element

2. One ion of the element

3. 12 u of an element

4. One atom of the element

Q. why is entropy positive in ideal solution ?

Q.

The number of shells in the electronic arrangement of Calcium(20) is equal to 4

1. 2

2. 1

Q. If the maximum shell of electron (N shell) can contain 32 electrons, then why it can contain a maximum of only 8 valence electrons? Please explain me this in detail.

Q.

A molecule of sulphur is monoatomic

1. True
2. False

Q. The particles of a solution are smaller than 1 nm in diameter.

1. True
2. False

Q.

Percentage of nitrogen in Earth's atmosphere is:

1. 78.08%

2. 91.08%

3. 85.08%

4. 65.08%

Q. Deduce the number of neutrons from the atomic number (Z) and mass number (A).

Q. Explain the monovalency of the element sodium.

Q. The chemical symbol for sodium is____________

1. nan
2. Sd
3. Na

4. So

Q. What will happen to the rate of the reaction if the concentration of a reactant is increased?

Q.

Deuterium is an isotope of hydrogen and is represented by ${}_1^2\text{H}$. How many deuterium atoms are present in heavy water?

1. 3

2. 4

3. 1

4. 2

Q.

On cooling down a substance, there is a loss of heat and the kinetic energy of its molecules ____________.

1. increases

2. decreases

3. remains the same.

4. None of these

Q.

What do the symbols H₂, S, and O₄ mean in the formula H₂SO_4.

Q.

Assertion: Mass of an atom is mainly of the nucleus similar.

Reason: The nucleus contains both protons and neutrons.

1. Both assertion and reason are correct and the reason is the correct explanation for assertion.

2. Both assertion and reason are correct and the reason is not the correct explanation for the assertion.

3. The assertion is correct but the reason is incorrect.

4. The assertion is incorrect but the reason is correct

Q. Electrons, protons and neutrons are the fundamental particles of an atom. Identify the correct option regarding an atom.

1. The number of protons is always equal to the number of electrons.
2. The number of protons is always equal to the number of neutrons.
3. The number of protons is greater than the number of electrons.
4. The number of electrons is greater than the number of protons.

Q.

Calculate the number of moles of hydrogen atom in 72 gms of water.

1. 2

2. 4

3. 6

4. 8

Q.

What do you understand by the term specific latent heat of fusion? State its CGS and SI unit.

Q.

The following diagram shows the various shells. The maximum number of electrons that can be accomodated in M shell is _______ .

1. 18

2. 32

3. 8

4. 2

Q. An atom of an element has electronic configuration 2, 8, 2. To which group does it belong?

1. 4th group
2. 2nd group
3. 3rd group
4. 6th group

Q. What is de broglie theory

Q.

Periodic properties of elements refer to the properties recurring at regular intervals.

1. False

2. True

Q.

The following arrangement of elements represents which type of early classification?

1. Newland's Law of Octaves

2. Dobereiner's Law of Triads

3. Mendeleev's Periodic Table

4. Modern Periodic Table