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Section 3: How Atoms Differ

How Atoms Differ


1.	What is the name for atoms of an element that have different masses? Need a Hint?
		A)	isotopes
		B)	isomers
		C)	allotropes
		D)	alloforms


2.	The atomic number of an element is defined by its number of ________. Need a Hint?
		A)	protons
		B)	neutrons
		C)	electrons
		D)	nuclei


3.	How many protons are present in an atom potassium-39? Need a Hint?
		A)	19
		B)	20
		C)	39
		D)	58


4.	The sum of the protons and neutrons in a nucleus is __________. Need a Hint?
		A)	the atomic number
		B)	the mass number
		C)	Avogadro’s number
		D)	the element number


5.	What is the name of the element that has an atomic number of 3? Need a Hint?
		A)	lanthanum
		B)	lithium
		C)	beryllium
		D)	helium


6.	Which of the following is a correct statement about a neutral atom? Need a Hint?
		A)	Neutrons are present in the nucleus.
		B)	The atoms carry a positive or a negative charge.
		C)	The atom has the same number of proton and electrons.
		D)	The atom is radioactive.


7.	Which of the following is true for any atom? Need a Hint?
		A)	atomic number = number of protons = number of electrons
		B)	atomic number = number of neutrons = number of electrons
		C)	mass number = number of protons = number of electrons
		D)	mass number = number of protons = number of neutrons


8.	Which of the following statements concerning hydrogen is false? Need a Hint?
		A)	All hydrogen isotopes have one proton.
		B)	All hydrogen isotopes have one electron.
		C)	All hydrogen isotopes have one neutron.
		D)	Hydrogen’s electron is not found in the nucleus.


9.	An atom of an element contains eight electrons. What is the identity of this element? Need a Hint?
		A)	nitrogen
		B)	oxygen
		C)	fluorine
		D)	carbon


10.	How is the atomic mass unit (amu) defined? Need a Hint?
		A)	1/12 the mass of a carbon-12 atom
		B)	1/14 the mass of a nitrogen-14 atom
		C)	1/13 the mass of a carbon-13 atom
		D)	1/16 the mass of an oxygen-16 atom