Look at this picture of Argon off the periodic table. Which of the following is true for this element?

• 18 protons

• 40 protons

• 22 protons

• 21.9 protons

The atomic mass of an atom is equal to

• number of protons plus number of neutrons

• number of protons plus number of electrons

• number of electrons plus the number of neutrons

The atomic mass of an atom is equal to

• number of protons plus number of neutrons

• number of protons plus number of electrons

• number of electrons plus the number of neutrons

The number of these determines which element an atom is.

• neutrons
• electrons
• protons

How is the number of neutrons in the nucleus of an atom calculated?

• Add the number of e- and p+ together
• Subtract the number of e- from p+
• Subtract the number of p+ from the mass number
• Add the mass number to the number of e-

An atom has 10 protons, 15 neutrons and 10 electrons what is its mass number.

• 20

• 10

• 35

• 25

Where is most of the mass in an atom located?

• in the nucleus
• in the protons
• in the neutrons
• in the electrons

An atom has an atomic number of 15 and a mass number of 31. How many protons are there in the atom?

• 15
• 31
• 16
• 47

The atomic number of an element that has 9 protons, 9 electrons, and 10 neutrons is _____.

• 9
• 10
• 19
• 28

The period for Bromine is ___________.

• 3
• 2
• 4