CHEM Ch. 3 Review

Neutral atoms contain equal numbers of

• Electrons and neutrons.

• Protons and neutrons.

• Protons and electrons.

• Protons, electrons, and neutrons.

The following atomic symbol for beryllium indicates what? $_4^9Be$  

• Atomic number is 4.

• Atomic number is 9.

• Mass number is 4.

• Atomic number is equal to 9 - 4.

Tags

NGSS.MS-PS1-1

Rutherford’s gold-foil experiment led him to conclude that

• Thomson’s plum pudding model of the atom was accurate.

• Alpha particles were a poor choice for a bombardment material.

• A dense region of positive charge existed somewhere in the atom.

• Light was emitted by electrons returning to ground state.

An atom of potassium has 19 protons and 20 neutrons. Its mass number is

• 9

• 19

• 20

• 39

The units of molar mass are

• g/mol

• mol/g

• amu/mol

• amu/g

The average atomic mass of an element is

• the mass of one isotope of the element.

• the weighted average of all naturally occurring isotopes of the element.

• the same as the atomic number of the element.

• the sum of the number of neutrons and protons in an atom.

In a glass tube attached to a voltage source, electrical current passes from the negative electrode, called the _____, to the other electrode

• cathode

• anode

• electron

• millikan

In Rutherford's experiments, most of the particles

• bounded back

• passed through the foil

• were absorbed by the foil

• combined with the foil

The smallest unit of an element that can exist either alone or in combination with other such particles of the same or different elements is the

• electron

• proton

• neutron

• atom

Tags

NGSS.MS-PS1-1

The tritium atom consists of

• one proton, two neutrons, and two electrons

• one proton, one neutron, and one electron

• one proton, two neutrons, and one electron

• two protons, one neutron, and one electron