Chemistry Daily 10’s

1. Chemistry Daily 10’s Week 4

2. 1 1. Isotopes are atoms of the same element that have different a. principal chemical properties. b. masses. c. numbers of protons. d. numbers of electrons.

3. 2. The total number of protons and neutrons in the nucleus of an atom is its a. atomic number. b. Avogadro number. c. mass number. d. average atomic mass.

4. 2 1. As the atomic number increases, the number of electrons in a neutral atom a. decreases. b. increases. c. remains the same. d. is undetermined.

5. 2. The average atomic mass of an element is the average of the atomic masses of its a. naturally occurring isotopes. b. two most abundant isotopes. c. radioactive isotopes. d. artificial isotopes.

6. 3 1. Chlorine has atomic number 17 and mass number 35. It has a. 17 protons, 17 electrons, and 18 neutrons. b. 35 protons, 35 electrons, and 17 neutrons. c. 17 protons, 17 electrons, and 52 neutrons. d. 18 protons, 18 electrons, and 17 neutrons.

7. 2. Phosphorus-33 (atomic number 15) contains a. 33 protons. b. 18 neutrons. c. 33 neutrons. d. 18 protons.

8. 4 1. What does the 4 in represent? a. the mass number b. the atomic number c. the number of protons d. the number of neutrons

9. 2. What does the 218 in polonium-218 represent? a. the mass number b. the atomic number c. the mass defect d. the neutron number

10. 5 1. What is the half-life of an isotope if 125 g of a 500 g sample of the isotope remain after 3.0 years? a. 1.5 years b. 2.5 years c. 3.5 years d. 4.5 years

11. 2. Which of the following processes produces nuclei of lower mass than the reactants? a. fission b. fusion c. Both (a) and (b) d. Neither (a) nor (b)

12. Answers & Standards • 1.1 – b – sc3a,d • 1.2 - c – sc3c,d • 2.1 - b – sc3c,d • 2.2 - a – sc3c,d • 3.1 – a – sc3a • 3.2 – b – sc3a • 4.1 – a – sc3a • 4.2 – a – sc3a • 5.1 – a – sc1a • 5.2 – a – sc1a