Atomic Models

Which letter represents an electron?

• A

• B

• C

• D

• E

Which of the following is correct?

• Protons (positive);

  Neutrons (negative);

  Electrons (neutral)

• Protons (positive); Neutrons (neutral); Electrons (negative)

• Protons (negative);

  Neutrons (neutral);

  Electrons (positive)

• Protons (neutral);

  Neutrons (positive);

  Electrons (negative)

How many neutrons does Phosphorus have? ...remember APE MAN

• 46

• 31

• 15

• 16

What is the atomic number of this atom?

• 7

• 14

• 21

• 9

Valence electrons determine an element's reactivity (chemical properties). How many valence electrons does this atom have?

• 8

• 2

• 1

• 11

What is the mass of this atom?

• 10

• 9

• 6

• 3

How many electrons can fit on the first two shells (energy levels)?

• 1 electron on the first and 2 electrons on the second

• 10 electrons on the first and 20 electrons on the second

• 2 electrons on the first and 8 electrons on the second

• 3 electrons on the first and 7 electrons on the second

Which of the following determines the identity of the element? (if you know this, then you can find out which element it is)

• The number of protons

• The mass

• The number of neutrons

• The number of electrons

Answer explanation

the mass can be different, even with the same element. For example, Carbon usually has a mass of about 12 amu, but there are carbons with a mass of 13 and even 14 amu. Electrons usually equal the protons, but electrons can be gained or lossed by an atom (ions)

A student needs to know which element this is? What is the first thing she should be counting?

• A

• B

• C

• D

Answer explanation

She needs to know the number of protons. This is also the atomic number, which identifies the element.

Which Element is this?

• Hydrogen (H)

• Helium (He)

• Lithium (Li)

• Neon (Ne)