The Compounds and Chemical Change Test consists of 20 questions. Correct answers will be provided after your answers have been submitted. If they are available, possible solutions can be accessed by clicking an additional link at the bottom of the answer, which will open a problem solution screen. If you bring up such a solution screen be sure to close it by clicking the button in the upper left corner or upper right corner.

Have a fun learning experience!

1		The smallest unit of an element that can exist alone or in combination with other elements is the
			A)	atom.
			B)	molecule.
			C)	ion.
			D)	electron.
2		Ozone is a form of oxygen that is
			A)	monatomic.
			B)	diatonic.
			C)	triatomic.
			D)	tetratomic.
3		Chemical energy is stored within molecules as
			A)	thermal energy.
			B)	internal activation energy.
			C)	internal potential energy.
			D)	kinetic energy of the nucleus.
4		The outer electrons of an atom that participate in chemical bonding are called the __?__ electrons.
			A)	reactant.
			B)	valence.
			C)	net.
			D)	product.
5		Which of the following represents the most stable outer orbital arrangement of electrons after a chemical reaction?
			A)	1 electron.
			B)	3 electrons.
			C)	6 electrons.
			D)	8 electrons.
6		The element sodium (Na) has how many valence electrons?
			A)	1
			B)	2
			C)	7
			D)	8
7		In a chemical reaction the element sodium (Na) will
			A)	lose an electron.
			B)	lose two electrons.
			C)	gain an electron.
			D)	neither gain nor lose electrons.
8		Ionic bonds are formed when
			A)	electrons are transferred from the excited to the ground state.
			B)	electrons are transferred from the ground state to the excited state.
			C)	electrons are transferred between atoms.
			D)	atoms share electrons.
9		Covalent bonds are formed when
			A)	electrons are transferred from the excited to the ground state.
			B)	electrons are transferred from the ground state to the excited state.
			C)	electrons are transferred between atoms.
			D)	atoms share electrons.
10		The number of atoms in a molecule of ammonium sulfate, (NH4)2SO4, is
			A)	4.
			B)	10.
			C)	14.
			D)	15.
11		When the atoms of a metal combine chemically with the atoms of a nonmetal, the nonmetal ions tend to
			A)	become positive ions.
			B)	remain neutral.
			C)	become negative ions.
			D)	share electrons.
12		A crystal grain of potassium chloride is made up of
			A)	K- and Cl+ ions.
			B)	K+ and Cl- ions.
			C)	molecules of KCl.
			D)	atoms of K and Cl.
13		The correct symbol for a magnesium ion is
			A)	Mg+
			B)	Mg-
			C)	Mg2+
			D)	Mg2-
14		The formula of a compound formed when aluminum (Al) combines with oxygen (O) is
			A)	AlO
			B)	Al3O2
			C)	Al2O2
			D)	Al2O3
15		The sulfate ion is (SO4)2- so the formula for calcium sulfate would be
			A)	CaSO4
			B)	Ca2SO4
			C)	Ca2(SO4)2
			D)	Ca2(SO4)3
16		The number of oxygen atoms in a molecule of copper(II) phosphate, Cu3(PO4)2, is
			A)	2
			B)	4
			C)	6
			D)	8
17		If the absolute difference in electronegativity between two bonded atoms is 2.0, the type of bond is
			A)	ionic.
			B)	polar covalent.
			C)	covalent.
			D)	none.
18		Ionic compounds are usually composed of
			A)	two metals.
			B)	two nonmetals.
			C)	a metal and a nonmetal.
			D)	a metal and a semiconductor.
19		If the correct formula for sodium bicarbonate is NaHCO3, then the formula for calcium bicarbonate would be
			A)	CaHCO3
			B)	Ca(HCO3)2
			C)	Ca2HCO3
			D)	CaHCO2
20		The formula for the covalent compound of tetraphosphorus trisulfide would be
			A)	P3S3
			B)	P3S4
			C)	P4S3
			D)	P4S4