chemistry test

How many electrons does the pictured krypton atom contain?

• 84
• 36
• 48
• 120

How many electrons on in this atom of nitrogen?

• 15
• 7
• 3
• 10

What does the number after Carbon-12 represent?

• the atomic mass
• the ion charge
• the number of neutrons
• the number of protons

What element is this?

• Sodium
• Magnesium
• Carbon
• Oxygen

An atom has 16 protons and 18 electrons.  What is the charge on the atom?

• 0 (neutral)
• +2
• -2
• -18

An atom has 17 protons, 18 electrons, and 18 neutrons.  What is the charge of this atom?

• 0 (neutral)
• +1
• -1
• +18

An atom has 56 protons, 81 neutrons, and 54 electrons.  What is the mass of this atom?

• 137
• 110
• 81
• 56

What is an isotope?

• An atom with a charge
• The same elements that have different masses
• An atom with more protons than electrons
• Two elements with the same number of neutrons

If an atom has a mass of 128 amu and has 51 protons, how many neutrons would be in the nucleus?

• 128
• 77
• 51
• 179

What is the charge for the atom in the diagram?

• 0 (neutral)
• +3
• -3
• -10