Science Unit 3 Test Review (set 1 of 2)

By reading the periodic table, you can find out how many __________ a certain element has.


Different atoms combine in different ways to form all the different things we see around us. How can an element's position in the periodic table tell you how it might combine with other elements to form a compound?

Elements on opposite sides of the periodic table combine easily.

What can an element's atomic number tell you about its state of matter?

It can't tell you anything about the element's state of matter.

How can knowing the number of electrons in the balanced atom of an element tell you the position of the element on the periodic table?

In a balanced atom, The number of protons in an atom is equal to the element's atomic number. So, by knowing the number of electrons, you know the element's atomic number.

Water freezes when _________.

its molecules slow down enough.

Why do sodium (Na) and chlorine (Cl) combine easily?

They are located on opposite sides of the periodic table.

Why does ice have three dimensions?

Because the atoms that make up water have three dimensions.

Two like atoms combine to form _______________.


The chemical formula of a water molecule is H2O. How many kinds of elements does water contain?


Why isn't water found on the periodic table?

It is a compound. The periodic table only lists elements.

HCl is hydrochloric acid. What two elements make up the acid?

hydrogen and chlorine

To find the atomic weight of a compound, what might you do?

Add together the atomic weight of each of the elements that make up the compound.

How many helium atoms does water (H2O) contain?


Water, ice, and water vapor are ________.

all the same type of compound.

Because water expands as it freezes, ________.

fish can live through the winter.

Which number is written above an element's chemical symbol?

atomic number

An element has an atomic number of 10. How many electrons does it have swirling around the nucleuses of its atoms?