Periodic Table

Q.

Atomic mass of an element is equal to the sum of?

1. Electron and neutron

2. Proton and neutron

3. None of the above

4. Electron and proton

Q.

The mass of a neutron is less than the mass of electron.

1. True
2. False

Q.

Atomic number is also known as proton number

1. True
2. False

Q.

Who discovered neutron? What is the contribution of neutron in the mass of an atom?

Q. The positions of three elements A, B and C in the periodic table are shown below:

Group 16	Group 17
--------------	------------
--------------	A
--------------	------------
B	C

(a) State whether A is a metal or non-metal.
(b) State whether C is more reactive or less reactive than A.
(c) Will C be larger or smaller in size than B ?

Q. State true or false.
The mass of an atom is due to the mass of its nucleus and the nucleus of an atom contains protons and neutrons together called as nucleons.

1. True
2. False

Q.

Arrange the following statements in chronological order:

1)Some elements be grouped in sets of three elements in the increasing order of their atomic weights in which the atomic weight of the middle element was found to be the arithmetic mean of the atomic weights of the other two elements.

2)The physical and chemical properties of elements are periodic functions of their atomic numbers.

3)The physical and chemical properties of elements are periodic functions of their atomic weights.

4)When elements are arranged in the increasing order of their atomic weights, the eighth element resembles the first in physical and chemical properties just as the eighth note on a musical scale resembles the first one.

1. 1432

2. 1342

3. 4213

4. 2431

Q. Explain why the valence electrons in $He$ can be found at the same peak and therefore the same ionization energy.

1. The electrons are moving too quickly to distinguish on PES.
2. The electrons in the $1s$ orbital are identical and cannot be distinguished in PES.
3. PES is not refined enough to separate electrons in different energy level.
4. The electrons are too small to distinguish on PES.

Q. State true or false.
Periodic properties of elements refer to the properties recurring at regular intervals.

1. True
2. False

Q. The mass number of an atom tells us about its atomic weight. What is the atomic weight of carbon?

1. 6 units
2. 18 units
3. 12 units
4. 36 units