L2.1 Check: Atomic Structure

What does the atomic number of an element represent?

• The number of neutrons in the nucleus
• The number of electrons in the outermost shell
• The number of protons in the nucleus
• The total number of protons and neutrons in the nucleus

What does the mass number of an element represent?

• The number of protons in an atom
• The number of electrons in an atom
• The total number of protons and neutrons in an atom
• The total number of protons and electrons in an atom

What are isotopes?

• Isotopes are elements with the same number of protons but different number of neutrons
• Isotopes are elements with the same number of neutrons but different number of protons
• Isotopes are elements with the same number of electrons but different number of protons
• Isotopes are elements with the same number of protons but different number of electrons

How are isotopes different from each other?

• Isotopes differ in the number of protons they have
• Isotopes differ in the number of electrons they have
• Isotopes differ in the number of neutrons they have
• Isotopes differ in the number of quarks they have

How are isotopes similar to each other?

• They have the same number of protons
• They have the same number of electrons
• They have the same atomic weight
• They have the same number of neutrons

What does the atomic mass represent?

• The weighted average of all of an element’s isotopes

• The total number of protons and neutrons in an atom

• The sum of the masses of all the electrons in an atom

• The total number of protons, neutrons, and electrons in an atom

Element symbol: O

Atomic number: ​ (a)  

Mass number: 16

Number of protons: ​ (b)  

Number of neutrons: ​ (c)  

Number of electrons: ​ (d)  

• 8
• 16
• 4
• 24

Element symbol: ​ (a)  

Atomic number: 13

Mass number: ​ (b)  

Number of protons: ​ (c)  

Number of neutrons: 14

Number of electrons: ​ (d)  

• 13
• Al
• C
• N
• As
• 27
• 26
• 14
• 28
• 47

Which of these can never change in an atom during an ordinary physical or chemical change?

• protons

• neutrons

• electrons

Element symbol: ​ (a)  

Atomic number: ​ (b)  

Mass number: 31

Number of protons: 15

Number of neutrons: ​ (c)  

Number of electrons: ​ (d)  

• P
• O
• Ph
• S
• 15
• 16
• 30
• 31
• 10
• 45