revision p4

revision p4

1. A becquerel is one decay per second

2. some substances are classed as 'radioactive'

3. if the substances are known as 'radioactive' that means they are unstable.

4. The substances continuously give out radiation at random intervals

5. The process is called 'radioacive decay'

6. Alpha-two protons and two neutrons

7. Beta-electron from the nucleus

8. Gamma-electromagnetic radiation

9. The atomic number tells us how many protons and electrons an element has.

10. The atomic mass tells us the total number of protons and neutrons an element has.

11. The number of protons and the number of electrons in an atom are always equal.

12. Two atoms of the same element with the same number of protons but a different number of neutrons are called symbol.

13. If an atom loses or gains an electron it becomes an ion.

14. Atomic number-number of protons in the nucleus of an atom.

15. The top number is the mass number.

    • The bottom number is the atomic number.