Matching

 

Match each item with the correct statement below.

a.

proton

d.

electron

b.

nucleus

e.

neutron

c.

atom

 

 

 

____ 1. the smallest particle of an element that retains the properties of that element

 

____ 2. a positively charged subatomic particle

 

____ 3. a negatively charged subatomic particle

 

____ 4. a subatomic particle with no charge

 

____ 5. the central part of an atom, containing protons and neutrons

 

Match each item with the correct statement below.

a.

mass number

d.

atomic mass

b.

atomic mass unit

e.

isotope

c.

atomic number

 

 

 

____ 6. atoms with the same number of protons, but different numbers of neutrons in the nucleus of an atom

 

____ 7. the total number of protons and neutrons in the nucleus of an atom

 

____ 8. the number of protons in the nucleus of an element

 

____ 9. the weighted average of the masses of the isotopes of an element

 

____ 10. one-twelfth the mass of a carbon atom having six protons and six neutrons

 

Multiple Choice

Identify the choice that best completes the statement or answers the question.

 

____ 11. Who was the man who lived from 460B.C.370B.C. and was among the first to suggest the idea of atoms?

a.

Atomos

c.

Democritus

b.

Dalton

d.

Thomson

 

 

____ 12. The smallest particle of an element that retains the properties of that element is a(n) ____.

a.

atom

c.

proton

b.

electron

d.

neutron

 

 

____ 13. Dalton hypothesized that atoms are indivisible and that all atoms of an element are identical. It is now known that ____.

a.

all of Dalton's hypotheses are correct

b.

atoms of an element can have different numbers of protons

c.

atoms are divisible

d.

all atoms of an element are not identical but they must all have the same mass

 

 

____ 14. Why did J. J. Thomson reason that electrons must be a part of the atoms of all elements?

a.

Cathode rays are negatively-charged particles.

b.

Cathode rays can be deflected by magnets.

c.

An electron is 2000 times lighter than a hydrogen atom.

d.

Charge-to-mass ratio of electrons was the same, regardless of the gas used.

 

 

____ 15. Which of the following is true about subatomic particles?

a.

Electrons are negatively charged and are the heaviest subatomic particle.

b.

Protons are positively charged and the lightest subatomic particle.

c.

Neutrons have no charge and are the lightest subatomic particle.

d.

The mass of a neutron nearly equals the mass of a proton.

 

 

____ 16. All atoms are ____.

a.

positively charged, with the number of protons exceeding the number of electrons

b.

negatively charged, with the number of electrons exceeding the number of protons

c.

neutral, with the number of protons equaling the number of electrons

d.

neutral, with the number of protons equaling the number of electrons, which is equal to the number of neutrons

 

 

____ 17. The particles that are found in the nucleus of an atom are ____.

a.

neutrons and electrons

c.

protons and neutrons

b.

electrons only

d.

protons and electrons

 

 

____ 18. As a consequence of the discovery of the nucleus by Rutherford, which model of the atom is thought to be true?

a.

Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.

b.

The nucleus is made of protons, electrons, and neutrons.

c.

Electrons are distributed around the nucleus and occupy almost all the volume of the atom.

d.

The nucleus is made of electrons and protons.

 

 

____ 19. An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are ____.

a.

152 protons and 76 electrons

c.

38 protons and 38 electrons

b.

76 protons and 0 electrons

d.

76 protons and 76 electrons

 

 

____ 20. What does the number 84 in the name krypton-84 represent?

a.

the atomic number

c.

the sum of the protons and electrons

b.

the mass number

d.

twice the number of protons

 

 

____ 21. Isotopes of the same element have different ____.

a.

numbers of neutrons

c.

numbers of electrons

b.

numbers of protons

d.

atomic numbers

 

 

____ 22. The mass number of an element is equal to ____.

a.

the total number of electrons in the nucleus

b.

the total number of protons and neutrons in the nucleus

c.

less than twice the atomic number

d.

a constant number for the lighter elements

 

 

____ 23. Using the periodic table, determine the number of neutrons in O.

a.

4

c.

16

b.

8

d.

24

 

 

____ 24. How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125 contain?

a.

50 protons, 50 electrons, 75 neutrons

c.

120 neutrons, 50 protons, 75 electrons

b.

75 electrons, 50 protons, 50 neutrons

d.

70 neutrons, 75 protons, 50 electrons

 

 


____ 25. Which of the following statements is NOT true?

a.

Atoms of the same element can have different masses.

b.

Atoms of isotopes of an element have different numbers of protons.

c.

The nucleus of an atom has a positive charge.

d.

Atoms are mostly empty space.

 

 

____ 26. If E is the symbol for an element, which two of the following symbols represent isotopes of the same element?

1. E

2. E

3. E

4. E

 

a.

1 and 2

c.

1 and 4

b.

3 and 4

d.

2 and 3

 

 

____ 27. Which of the following sets of symbols represents isotopes of the same element?

a.

J J J

c.

M M M

b.

L L L

d.

Q Q Q

 

 

____ 28. How is the number of neutrons in the nucleus of an atom calculated?

a.

Add the number of electrons and protons together.

b.

Subtract the number of electrons from the number of protons.

c.

Subtract the number of protons from the mass number.

d.

Add the mass number to the number of electrons.

 

 

____ 29. In which of the following is the number of neutrons correctly represented?

a.

F has 0 neutrons.

c.

Mg has 24 neutrons.

b.

As has 108 neutrons.

d.

U has 146 neutrons.

 

 

____ 30. What unit is used to measure weighted average atomic mass?

a.

amu

c.

angstrom

b.

gram

d.

nanogram

 

 

____ 31. The atomic mass of an element is the ____.

a.

total number of subatomic particles in its nucleus

b.

weighted average of the masses of the isotopes of the element

c.

total mass of the isotopes of the element

d.

average of the mass number and the atomic number for the element

 

 

____ 32. The atomic mass of an element depends upon the ____.

a.

mass of each electron in that element

b.

mass of each isotope of that element

c.

relative abundance of protons in that element

d.

mass and relative abundance of each isotope of that element

 

 

Short Answer

 

33. List the number of protons, neutrons, and electrons in C.

 

34. Chlorine has two naturally occurring isotopes, Cl-35 and Cl-37. The atomic mass of chlorine is 35.45. Which of these two isotopes of chlorine is more abundant?

 

35. A fictitious element X is composed of 10.0 percent of the isotope , 20.0 percent of the isotope , and 70.0 percent of the isotope . Estimate the atomic mass of element X.

 

36. The element chromium has four naturally occurring isotopes. Use the relative abundance of each to calculate the average atomic mass of chromium.

50Cr = 4.34%, 52Cr = 83.79%, 53Cr = 9.50%, 54Cr = 2.37%.

 

Numeric Response

 

37. Use the periodic table to determine the number of electrons in a neutral atom of lithium.

 

38. Use the periodic table to determine the number of protons in an atom of barium.

 

39. How many protons are present in an atom of Be-9?

 

40. What is the total number of subatomic particles in the nucleus of an atom of Bi?

 

41. What is the atomic number for an element with 41 neutrons and a mass number of 80?

 

42. What is the mass number for an oxygen atom that has 10 neutrons in its nucleus?

 

Essay

 

43. What observations by Rutherford led to the hypothesis that atoms are mostly empty space, and that almost all of the mass of the atom is contained in an atomic nucleus?

 

44. Explain how the atoms of one element differ from those of another element.

 

45. In what way are two isotopes of the same element different? Explain why isotopes of the same element have the same chemical behavior