Atoms Review

Phosphorous-31 has an abundance of 94.2%. Phosphorous-30 has an abundance of 5.1%. Phosphorous-32 has an abundance of 0.7%. What is the atomic mass of Phosphorous?

• 30.96
• 32
• 23.00
• 36.90

J.J. Thomson used a cathode ray tube to find what particle in the atom?

• Proton
• Neutron
• Electron

Oxygen has 8 protons. What is oxygen's atomic number?

• 16
• 8
• 15.999
• 0

A neutral atom of Carbon-13 has ________ electrons and _________ neutrons

• 13, 13
• 6, 6
• 7, 7
• 6, 7

Ernest Rutherford discovered that atoms were mostly _________________. 

• negatively charged
• positively charged
• electrons
• empty space. 

Isotopes are atoms of the same element that have the same number of __________ but different number of __________ . Therefore, isotopes of the same element have different masses. 

• protons, neutrons
• protons, electrons
• neutrons, protons
• electrons, protons

What is true about a neutral atom?

• The number of protons equal the number of neutrons
• The number of protons equal the number of electrons
• The number of neutrons equal the number of electrons
• The number of protons, neutrons, and electrons are all different

Do the following atoms belong to the same element? Explain
       Aluminum-27
       An atom with 14 protons and 13 neutrons

• Yes because they have the same number of protons
• Yes because they have the same mass
• No because they have different number of protons
• No because they have different number of neutrons

An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?

• 9.012, Beryllium
• 12.011, Carbon
• 6.941, Lithium
• 10.812, Boron

What scientist is best known for his gold foil experiment?

• J.J. Tomson
• Ernest Rutherford
• John Dalton
• Democritus