Atoms and Elements

Which element is least reactive?

• Neon, because it has two energy levels with eight electrons in the second level

• Chlorine, because it has three energy levels with seven electrons in the third level

• Gallium, because it has four energy levels with three electrons in the fourth level

• Tin, because it has five energy levels with four electrons in the fifth level

Which has the greatest density? D=M/V

• 1

• 2

• 3

• 4

Valence Electrons are related to

• Period number

• Group number

• Atomic number

• Atomic mass

What is the atomic number?

• 16

• 32

Name the atom with 8 protons, 8 neutrons, and 8 electrons

• Sulfur

• Nitrogen

• Oxygen

• Carbon

How many elements? C₁₀H₁₂N₂O

• 10

• 12

• 25

• 4

How many total atoms? C₁₀H₁₂N₂O

• 10

• 12

• 25

• 4

Clarissa is conducting an experiment. She carefully measures out 15g of baking soda into a bag. She then carefully measures out 25ml of vinegar (which is equal to 25g), pours the vinegar into the bag and immediately seals it. She then watches as bubbles start to form and the bag fills up with gas. According to the Law of Conservation of Mass, how much should the bag weigh after the reaction has finished?

• 10

• 40

• 25

• 35

Which is NOT evidence of a chemical reaction?

• Phase change

• Color Change

• Gas Production

• Light Production

What element is this? 

• Oxygen
• Carbon
• Hydrogen
• Helium