Homework #7: LT 1-8, 10

Which particle has the least mass?

• a helium atom

•  a hydrogen atom

• a proton

• an electron

Which statement describes the charge and location of an electron in an atom?

• An electron has a positive charge and is located inside the nucleus.

•  An electron has a negative charge and is located inside the nucleus.

• An electron has a positive charge and is located outside the nucleus.

•  An electron has a negative charge and is located outside the nucleus.

Which conclusion directly resulted from the “gold foil experiment”? (Choose two)

• Electrons are located in shells.

• Atoms are mostly empty space.

• Electrons have a small mass.

• Atoms are hard, indivisible spheres.

• The nucleus is small, positive, and dense

Which two atoms are isotopes of the same element?

• X and D

• A and D

• A and X

• Z and D

Which particles are found in the nucleus of an argon atom?

• atoms and neutrons

• electrons and atoms

•  protons and electrons

• protons and neutrons

The discovery of the electron as a subatomic particle was a result of

• the gold-foil experiment
  

• experiments with cathode ray tubes

• the bohr model

• the modern model 

What is the approximate mass number of an atom that contains 26 protons, 26 electrons and 19 neutrons?

• 45u

• 71u

• 26u

• 52u

What is the total number of neutrons in an atom of K-42? (K is Atomic #19)

• 20

• 42

• 19

• 23

True or False: Ground state configurations can be found directly on the Periodic Table.

• True

• False

• Depends on the number of electrons

• Depends on the atom

What is the number of electrons in an atom of sodium? (Sc is Atomic #21)

• 24

• 66

• 21

• 45