$\text{charge} = \#p^+ - \#e^-$

Question 1

Which statement best describes the difference between an atom and an element?

Accepted Answer

An atom is the smallest identifiable unit of an element, while an element is a substance that cannot be broken down into simpler substances.

Question 2

Which experiment led to the discovery that atoms have a dense nucleus?

Accepted Answer

Rutherford's gold foil experiment

Question 3

According to Dalton’s atomic theory, which of the following is NOT true?

Accepted Answer

Atoms of a given element can have different masses due to isotopes.

Question 4

Which of the following statements about electrical charge is correct?

Accepted Answer

Positive and negative charges attract each other, while like charges repel.

Question 5

A neutral atom of sodium ($Z = 11$) has how many electrons?

Accepted Answer

$11$

Question 6

Which property is typical of metals?

Accepted Answer

They are good conductors of heat and electricity.

Question 7

What is the charge of an ion with 17 protons and 18 electrons?

Accepted Answer

$-1$

Question 8

Which of the following elements is a metalloid and commonly used in semiconductors?

Accepted Answer

Silicon

Question 9

How many neutrons are in the isotope $^{37}_{17}Cl$?

Accepted Answer

$20$

Question 10

Which group in the periodic table contains the noble gases?

Accepted Answer

Group 8A

Question 11

A sample of chlorine contains 75.77% $^{35}Cl$ (mass = 34.97 amu) and 24.23% $^{37}Cl$ (mass = 36.97 amu). What is the atomic mass of chlorine?

Accepted Answer

$35.45$ amu

Question 12

Which of the following best explains why isotopes of the same element have different mass numbers?

Accepted Answer

They have different numbers of neutrons.

Question 13

Which element has the atomic number $Z = 6$?

Accepted Answer

Carbon

Question 14

What is the ion charge for a magnesium atom ($Z = 12$) that loses two electrons?

Accepted Answer

$2+$

Question 15

Which of the following is a correct isotope symbol for an atom with 10 protons and 12 neutrons?

Accepted Answer

$^{22}_{10}Ne$

Question 16

Which of the following elements is most likely to gain electrons during a chemical reaction?

Accepted Answer

Chlorine

Question 17

Which scientist is credited with proposing the periodic law based on recurring properties of elements?

Accepted Answer

Dmitri Mendeleev

Question 18

A technetium-99 ($^{99}Tc$) isotope is used in medical imaging. What makes it especially useful for this purpose?

Accepted Answer

It emits nuclear radiation that can be detected to image internal organs.

Question 19

Which of the following is the correct formula to calculate the charge of an ion?

Accepted Answer

$	ext{charge} = \#p^+ - \#e^-$

Question 20

Which of the following best describes the difference in mass between a proton and an electron?

Accepted Answer

A proton is nearly 2000 times as massive as an electron.

Atoms and Elements: Foundations of Matter (Chapter 4 Study Notes)

Study Guide - Practice Questions