Question 1

According to John Dalton's atomic theory, which statement is FALSE?

Accepted Answer

Atoms can be created or destroyed during chemical reactions.

Question 2

Which experiment led Ernest Rutherford to propose the nuclear model of the atom?

Accepted Answer

The gold foil experiment.

Question 3

Given the element annotation $$\mathrm{^{A}_{Z}X}$$, what does $$A$$ represent?

Accepted Answer

Mass number

Question 4

A neutral atom of $$\mathrm{^{120}Sn}$$ has how many protons, neutrons, and electrons?

Accepted Answer

50 protons, 70 neutrons, 50 electrons

Question 5

Which subatomic particle has a mass of $$9.109 	imes 10$$^{-31}$$ kg and a charge of -1.602$$ 	imes $$10^{-19} C$$?

Accepted Answer

Electron

Question 6

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 7

Iron has several isotopes. If $$^{56}Fe $$has 26 protons, how many neutrons does it have?

Accepted Answer

30

Question 8

Which of the following best describes the nucleus in Rutherford's atomic model?

Accepted Answer

It is a small, dense region containing protons and neutrons.

Question 9

If an atom has 17 protons, 18 neutrons, and 17 electrons, what is its mass number?

Accepted Answer

35

Question 10

Which statement about subatomic particles is TRUE?

Accepted Answer

Protons and neutrons have nearly the same mass.

Question 11

A sample contains 92.0% $$^{56}Fe ($$mass = 55.9349 u), 5.8% $$^{54}Fe ($$mass = 53.9396 u), and 2.2% $$^{57}Fe ($$mass = 56.9354 u). What is the average atomic mass of iron in this sample? (Round to two decimal places)

Accepted Answer

$$55.85 u$$

Question 12

Which of the following is NOT a postulate of Dalton's atomic theory?

Accepted Answer

Atoms can be converted into energy.

Question 13

Which isotope of hydrogen is radioactive?

Accepted Answer

Tritium

Question 14

An atom of $$^{35}Cl $$has how many neutrons?

Accepted Answer

17

Question 15

Which of the following best explains why atoms of the same element can have different masses?

Accepted Answer

They have different numbers of neutrons.

Question 16

A neutral atom of $$^{120}Sn $$loses two electrons. What is its resulting charge?

Accepted Answer

$$+2$$

Question 17

Which of the following is the correct symbol for an isotope of iron with 32 neutrons?

Accepted Answer

$$^{58}Fe$$

Question 18

Which statement about electrons is correct?

Accepted Answer

Electrons have a mass much smaller than protons.

Question 19

If an atom has 15 protons and 16 neutrons, what is its mass number and element symbol?

Accepted Answer

$$^{31}P$$

Question 20

Which of the following is a consequence of Dalton's atomic theory for chemical reactions?

Accepted Answer

Atoms are rearranged but not created or destroyed.

Foundations of Atomic Theory and Structure

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