Which of the following statements about the electron is incorrect?
1. It is a negatively charged particle
2. The mass of electron is equal to the mass of neutron
3. It is a basic constituent of all atoms
4. It is a constituent of cathode rays
Two atoms are said to be isobars if:
1. | They have the same atomic number but different mass numbers. |
2. | They have the same number of electrons but a different number of neutrons. |
3. | They have the same number of neutrons but different numbers of electrons. |
4. | Sum of the number of protons and neutrons is the same but the number of protons is different. |
Chlorine exists in two isotopic forms, Cl-37 and Cl-35, but its atomic mass is 35.5. This indicates the ratio of Cl-37 and Cl-35 is approximately:
1. 1:2
2. 1:1
3. 1:3
4. 3:1
Assertion (A): | All isotopes of a given element show the same type of chemical behaviour. |
Reason (R): | The chemical properties of an atom are controlled by the number of electrons in the atom. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Identify the pairs which are not of isotopes?
(a)
(b)
(c)
(d)
1. (a), (d)
2. (b), (c)
3. (c), (d)
4. (b), (d)
An isoelectronic pair among the following is -
(a) Na+, Mg2+
(b) Al3+, O-
(c) Na+, O2-
(d) N3-, Cl-
1. (a), (c)
2. (b), (c)
3. (c), (d)
4. (b), (d)