Unit 3 Exam Review

Elements on the periodic table is aranged in order of ___________.

• atomic mass
• atomic number
• valence electrons
• number of isotopes

Which definition below best defines the term "element"?

• A mixture of two or more substances that can be separated by physical means.
  

• A pure substance made of only one kind of atom and cannot be broken down into simpler substances by chemical means.
  

• A combination of two or more elements chemically bonded together.

• A substance that contains atoms with different numbers of protons.

The horizontal (side to side) rows in the Periodic Table are called

• groups

• families

• periods

• atomic numbers

The vertical (up and down) columns in the Periodic Table are called

• groups

• towers

• periods

• atomic numbers

Elements in the same group ________.

• have the same number of electron shells (size)

• have similar chemical properties

• increase in atomic mass but not in reactivity

• are arranged in horizontal rows on the periodic table

Elements in the same period ________.

• have the same number of valence electrons

• have the same number of electron shells/are similar in size

• have similar chemical properties.

• are arranged in vertical columns on the periodic table.

What does the atomic number of an element represent?

• The total number of protons in the nucleus of an atom.

• The combined number of protons and neutrons in an atom.

• The total number of electrons an atom can have.

• The average mass of all the isotopes of the element.

What is a chemical symbol?

• The abbreviation for the name of an element on the periodic table.

• A shorthand notation for a chemical reaction.

• A representation of the number of protons and neutrons in an atom.

• A symbol that shows the charge of an atom.

The first letter of the chemical symbol is always __________, and if there is a second letter, it is always __________.

• lowercase; uppercase

• uppercase; lowercase

• uppercase; uppercase

• lowercase; lowercase

What group is Calcium (#20) in?