06.05 Atomic Theory

A neutral atom of aluminum has 14 neutrons and 13 protons. How many electrons does this aluminum have? 1 13 14 27

13

Modern atomic theory states that atoms are neutral. How is this neutrality achieved? Equal number of neutrons and protons Equal number of protons and electrons More electrons than protons More neutrons than electrons

Equal number of protons and electrons

Which description best explains a molecular bonding? Donates electrons Shares electrons Charged ions attract Occurs between metals

Shares electrons

Rutherford's famous gold foil experiments shot heavy particles at a thin sheet of gold foil. What did he observe, and why did these observations eventually result in the addition of a nucleus to the atomic model? Some particles bounced off the foil, because there are positive particles spread throughout the atom. The heavy particles all passed straight through the foil, because the atoms are mostly empty space. Some of the heavy particles bounced off the foil, because there is a dense, positive area in the atom. The heavy particles all bounced off the foil, because the subatomic particles have mass and volume.

Some of the heavy particles bounced off the foil, because there is a dense, positive area in the atom.

The development of atomic theory was due to various scientists building upon hypotheses and research of past studies of the atom. True False

True

Isotopes of the same element always have the same ________. atomic mass number A-number Z-number neutrinos

Z-number

Isotopes of the same element have different numbers of ________. protons neutrons neutrons and electrons protons and electrons

neutrons