Matter
This term describes a substance made of only one type of atom.
What is an element?
This number identifies an element and equals its number of protons.
What is atomic number?
The trend that increases up and to the right across the periodic table.
What is electronegativity?
This type of bond forms when electrons are shared.
What is a covalent bond?
The correct name for CaCl₂.
What is calcium chloride? (Remember, in ionic bonding we do not use prefixes)
A mixture that has the same composition throughout.
What is a homogeneous mixture?
Atoms of the same element that differ in neutron number.
What are isotopes?
These three categories classify the elements on the table.
What are metals, nonmetals, and metalloids?
The seven diatomic elements can be remembered by this acronym.
Have
No
Fear
Of
Ice
Cold
Beer
The correct name for N₂O₅.
What is dinitrogen pentoxide?
This is the phase change from liquid to gas.
What is vaporization?
Rutherford’s gold foil experiment showed that the atom contains this.
What is a small, dense, positively charged nucleus?
Elements in the same group have the same number of these.
What are valence electrons?
The bond formed when electronegativity differences are between 0.5 and 1.7.
What is a polar covalent bond?
Magnesium and fluorine form this ionic compound.
What is MgF₂?
Burning wood is this type of change.
What is a chemical change?
This atomic model proposed electrons embedded in a positive sphere.
What is the plum pudding model?
These elements tend to lose electrons and form cations.
What are metals?
Lone pairs and bonds each count as one of these in VSEPR theory.
What are electron groups?
The correct formula for ammonium sulfate.
What is (NH₄)₂SO₄?
When two samples of the same compound show identical mass ratios of elements, they demonstrate this law.
What is the Law of Definite Proportions?
The sum of protons and neutrons in an atom.
What is mass number?
This radius-related trend decreases across a period.
What is atomic radius?
A molecule with four electron groups and one lone pair forms this shape.
What is trigonal pyramidal?
Naming a molecule incorrectly as tetrahedral instead of trigonal pyramidal ignores this key structural feature.
What is the lone pair on the central atom?
The law stating that matter cannot be created or destroyed in a chemical reaction.
What is the Law of Conservation of Mass?
The Greek term “atomos” means this, although it turned out to be incorrect.
What is indivisible?
The most electronegative element.
What is fluorine?
Multiple valid Lewis structures of a molecule demonstrate this phenomenon.
What is resonance?
This name is given to compounds with the general form MX₂ where the metal has a +2 charge.
What is “metal(II)” + root + “-ide”? (e.g., iron(II) bromide)