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)