Exploring Atoms, Ions, and Isotopes

What does the atomic number of an element represent?

• The number of electrons in the nucleus

• The average mass of the element

• The number of protons in the nucleus

• The number of neutrons in the nucleus

Why is the average atomic mass of an element usually a decimal?

• It is the mass of the element in grams

• It is an average of the masses of all isotopes considering their relative abundance

• It is the mass of the element in atomic mass units

• It represents the mass of the most common isotope

What happens to an atom when it loses an electron?

• It becomes a negative ion

• It gains a proton

• It becomes a positive ion

• It becomes neutral

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NGSS.HS-PS1-2

What is the overall charge of an atom that has gained an electron?

• It depends on the number of protons

• Negative

• Neutral

• Positive

Where is the charge of an ion written in the element symbol?

• Top right corner

• Bottom left corner

• Top left corner

• Bottom right corner

What does a positive charge on an ion indicate?

• The atom has lost protons

• The atom has gained electrons

• The atom has lost electrons

• The atom has gained protons

What are isotopes?

• Atoms of different elements with the same number of protons

• Atoms of the same element with different numbers of neutrons

• Atoms of different elements with the same number of neutrons

• Atoms of the same element with different numbers of protons

How many neutrons does Carbon-14 have?

• 8

• 7

• 14

• 6

How do you find the number of neutrons in an isotope?

• Multiply the atomic number by the mass number

• Subtract the atomic number from the mass number

• Add the atomic number to the mass number

• Divide the mass number by the atomic number

Where is the mass number written in the symbol for an isotope?

• Top left corner

• Top right corner

• Bottom right corner

• Bottom left corner