Help me with this homework please

1. The mass number of an atomic nucleus is its a) number of protons b) number of neutrons c) number of nucleons

d) number of electrons

2. The chemical properties of a neutral atom are determined by the a) number of protons in its nucleus b) the number neutrons in its nucleus c) the number of alpha particles in its nucleus

d) the number of nucleons in its nucleus.

3. An atomic nucleus is held together by a) the gravitational force b) the weak nuclear force c) the electromagnetic force

d) the strong nuclear force

4. Isotopes of a chemical element all have the same __________ number but have different numbers of_____________________.

5. The radioactive isotope 241Am,Americium-241, is used in household smoke detectors. This 95

isotope has a nucleus containing ________________ protons and __________ neutrons.

6. A nucleus of the isotope 241 Am undergoes an alpha decay to an isotope of the element Neptunian 95

(Np). The atomic number for Neptunian is ________________ while the number of neutrons for this isotope is______________.

7. The isotope 241Amhas a half-life of 432 years. How long does it take a given collection of 95

241Amnuclei to decay so that only a fourth of the original nuclei are left? ________________ 95

(Hint: How long does it take for half the original number to be left? And then half of those to be left, etc.?)

8. Nuclei that are radioactive have far more ____________ than_______________?

9. The most penetrating form of nuclear radiation is a) alpha particles b) beta particles c) gamma rays

d) x-rays

10. The iodine isotope 131I undergoes a radioactive decay to become an isotope of Xenon, 131Xe. 53 54

Complete the expression for this decay: 131 I 131 Xe + _____. This is an example of 53 54

__________decay.