Atoms have positively charged particles, negatively charged particles, and particles with no charge. Why is an atom electrically neutral?

• Atoms have the same number of electrons (negative charge) and protons (positive charge).
• An atom’s nucleus has only neutrons, which have no charge.
• Atoms contain subatomic particles and not electrically charged particles.
• Atoms have neutrons and protons in the nucleus, and they do not have a charge.

A baker removed a cake from a 177°C oven and placed it on the counter of a 25°C kitchen. According to the second law of thermodynamics, the cake temperature will _________, resulting in a final cake temperature very near ___________ °C.

• increase, 177°C
• decrease, 25°C
• stay the same, 177°C
• stay the same, 25°C

Uranium has three naturally occurring isotopes: uranium-238, uranium-235, and uranium-234. The atomic mass for uranium is 238.029 amu. Which of these three isotopes is most abundant? Explain.

• Uranium-234, because it is the lightest isotope.
• Uranium-235, because it is used in nuclear reactors.
• Uranium-238, because the average atomic mass is closest to 238.
• All three isotopes are equally abundant.

If you are going to draw the Bohr model of aluminum and sodium, how many electrons are found in the outermost shell of each element?

• Aluminum 3, Sodium: 1

• Aluminum 4, Sodium: 1

• Aluminum: 2, Sodium: 8

• Aluminum: 1, Sodium: 7

How do isotopes of the same element differ? How are they the same?

• They differ in number of protons but have the same neutrons.
• They differ in number of neutrons but have the same protons.
• They differ in number of electrons but have the same neutrons.
• They differ in number of protons and neutrons but have the same electrons.

What is the maximum number of electrons in the 3rd energy level? formula: 2n²

• 32
• 8

• 2

• 18

What is the noble gas electron configuration for phosphorus (P)?

• [Ne] 3s² 3p⁴
• [Ne] 3s² 3p⁶

• [Ne] 3s² 3p³

• [He] 2s² 2p⁶ 3s² 3p⁴

One property of electrons is that they move in the orbitals. How do electrons in the same orbital move?

• electrons spin in the same orbital
• electrons vibrate in the same orbital
• electrons bounce in the same orbital
• electrons slide in the same orbital

Based on the periodic table, which other element is likely to share common properties with Magnesium, or Mg?

• F
• Br
• Ca

• Na

If 12 g of hydrogen reacts with 96 g of oxygen to form water, how many grams of water are produced?

• 84 g
• 96 g
• 108 g
• 120 g