Chemistry Review

Use the periodic table to answer the question.

Out of all the lists below, which list contains the three elements that are most alike in their chemical properties?

• O, F, Ne

• Li, Mg, Sc

• Li, Na, K

• H, He, Li

Why is the periodic table so useful to scientists?

• It reminds them what the elements look like.

• It can be used to predict how they react.

• It lists the chemical formulas for all of the different compounds.

• It contains the recipes for a variety of different kinds of mixtures.

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All of the elements listed below are highly reactive metals except one. Which one is not a highly reactive metal?

• sodium (in group 1)

• magnesium (in group 2)

• carbon (in group 14)

• potassium (in group 1)

Suppose a neutral atom were to lose an electron. What would happen to the atom?

• It would become negatively charged.

• It would become positively charged.

• It would remain neutral.

• It would also lose a proton.

A typical atom of aluminum has 13 electrons and 14 neutrons. How many protons does the atom have?

• 1

• 13

• 14

• 27

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Elements in the same group on the periodic table tend to have similar physical and chemical properties. This is because these

elements:

• have the same number of protons in the nucleus of their atoms.

• have the same number of electrons in the outer energy levels of their atoms.

• have the same number of neutrons in the nucleus of their atoms.

• have the same number of total electrons surrounding the nucleus of their atoms.

This model represents an atom of neon, which is in group 18, the far right group of the periodic table of the elements. What does the element’s position in the table tell you about neon?

• It has 18 electrons.

• It accepts electrons.

• It gives up electrons.

• Its outer electron shell is full.

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How are protons and neutrons different?

• Protons are in the nucleus of the atom, while neutrons orbit the nucleus.

• Neutrons are in the nucleus of the atom, while protons orbit the nucleus.

• Protons have a positive charge, while neutrons have a negative charge.

• Protons have a positive charge, while neutrons have no charge.

Which of the following represents a molecule that is not a compound?

• CO₂

• Fe

• o₂

• CO

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The difference between elements and compounds is that_______.

• elements can be separated by physical means and compounds cannot

• elements cannot be separated by physical means and compounds can

• elements contain only one kind of atom and compounds contain more than one kind of atom

• elements contain more than one kind of atom and compounds contain only one kind of atom