Dad Su No Ku

Assessment
Chapter Test A


Chapter: Atoms: The Building Blocks of Matter
In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.

1. Neutral atoms contain equal numbers of
a. electrons and neutrons.
b. protons and neutrons.
c. protons and electrons.
d.protons, electrons, and neutrons.

2. The atomic symbol for beryllium, [pic], indicates that the
a. atomic number is 4.
b. atomic number is 9.
c. mass number is 4.
d. atomic number is equal to 9 ( 4.

3. The atomic mass of an atom of carbon is 12 amu, and the atomic mass of an atom of oxygen is 16 amu. To produce CO, 16 gof oxygen combine with 12 g of carbon. To produce CO2, 32 g of oxygen combine with 12g of carbon. The ratio of the mass of oxygen in CO2 to the mass of oxygen in CO is
a. 1:1.
b. 2:1.
c. 1:2.
d. 8:3.

4. Rutherford’s gold-foil experiment led him to conclude that
a. Thomson’s plum pudding model of the atom was accurate.b. alpha particles were a poor choice for a bombardment material.
c. a dense region of positive charge existed somewhere in the atom.
d. light was emitted by electrons returning to ground state.

5. Which of the following is not one of the five principles of Dalton’s theory?
a. Atoms of different elements combine in simple,whole-number ratios to form compounds.
b. All matter is made of indivisible, indestructible atoms.
c. All atoms have similar physical and chemical properties.
d. Chemical reactions consist of the combination, separation, or rearrangement of atoms.

Chapter Test A, continued


6. According to the law of definite proportions, any two samples of KCl willhave
a. the same mass.
b. slightly different molecular structures but the same two elements.
c. different densities.
d. the same elements in the same proportions by mass.

7. According to the law of conservation of mass, when sodium, hydrogen, and oxygen react to form a compound, the mass of the compound will be
a. equalto the sum of the masses of the reactants.
b. greater than the sum of the masses of the reactants.
c. less than the sum of the masses of the reactants.
d. either less than or equal to the sum of the masses of the reactants.

8. Thomson’s experiment showed that the charge-to-mass ratio of electrons was
a. greater with noble gasesthan for other gases.
b. less with noble gases than for other gases.
c. the same in all gases.
d. dependent on the element’s atomic mass.

9. An atom of potassium has 19 protons and 20 neutrons. Its mass number is
a. 9.
b. 19.
c. 20.
d. 39.

10. Which of the following is not equal to1.00 mol of carbon-12?
a. 6.022 ( 1023 carbon atoms
b. 12.0 g of carbon
c. 6.0 g of carbon
d. Both (b) and (c)

11. Compared with a mole of lead atoms, a mole of iron atoms
a. has more atoms.
b. has fewer atoms.
c. has the same number of atoms.
d. cannot be determined because iron ismagnetic.

12. The molar mass of an element is numerically equal to
a. the element’s average atomic mass.
b. the element’s average atomic number.
c. the number of electrons possessed by an element.
d. the percentage composition of the element by mass.

Chapter Test A, continued


13. To calculate the number of...