Ch. 18 PS test
What is the difference between ionic bonds and covalent bonds?
In covalent bonds the atoms share electrons and in ionic bonds the atoms transfer electrons.
what is the chemical formula for a bond between magnesium ions and chlorine ions?
MgCl2
Why are valence electrons important?
They are important because if an atom holds fewer valence electrons, the less stable it will become
electrons shared in a molecule are held more __ to the atoms with the larger nucleus
closely
a ___ bond is the force of attraction between atoms sharing electrons
covalent
in a covalent bond, atoms can form double or triple bonds depending on whether they share two or three pairs of ___
electrons
chemists use __ from the periodic table to write formulas for compounds
elements
to write __, use the oxidation numbers, their least common multiple, and use parentheses around the polyatomic ion before adding a subscript
formulas
What side of the Periodic Table contains the metals
left side
Ionic bonds form when atoms...
transfer of electrons
anions are __ ions
-
a polyatomic ion contains __ or more elements
2
elements that do not have full outer energy levels are more stable in ___
compounds
an ionic compound is held together by the __ __
ionic bond
when an atom __ an electron, it becomes a negatively charged ion
loses
when an atom __ an electron, it becomes a positively charged ion; a superscript indicates the charge
loses
use the name of the first element, the root name of the second element, and the suffix -ide to write the __ of binary ionic compound
name
to write names, write the name of the positive ion first; they write the name of the ___ ion
negative
the result of an ionic bond is a __ compound
neutral
covalent bonds form between...
nonmetals and nonmetals
in a ___ molecule, electrons are shared equally
nonpolar
Where are valence electrons found?
outermost energy level
a __ molecule has one end that is slightly negative and one end that is slightly positive although the overall molecule is neutral
polar
define polyatomic ion
positively or negatively charged, covalently bonded group of atoms
atoms can lose, gain, or __ electrons to get a stable outer energy level
share
atoms form compounds when the compound is more __ than the separate atoms
stable
If Nitrogen has 3 unpaired electrons, how many other atoms does it want to bond with?
three
cations are __ ions
+
How many electrons do most atoms want in order to fill their valence shell?
8
What is a metallic bond? Explain what properties it gives to metals.
A metallic bond is between a metal and another metal. Metallic bonds give properties to metals such as strength, ductility, malleability, thermal and electrical conductivity, luster and opacity.
contrast covalently bonded and ionically bonded chemicals using specific examples
Both Ionic and Covalent bonding lead to a stable molecule. The molecules that are created through iconic and covalent bonding are both electrically neutral. They are both formed in fixed quantities.
compare covalently bonded and ionically bonded chemicals using specific examples
Covalent bonding occurs when atoms have similar needs for electrons, it happens between a nonmetal and another nonmetal. Ionic bonding occurs when atoms have opposite needs for electrons, it happens between a metal and a nonmetal. Covalent bonds don't conduct electricity and ionic bonds conduct electricity besides in solids. Ionic Bonds have no definite shape and covalent bonds have definite shape. Ionic bonds have a high melting and boiling point and covalent bonds have a low melting and bonding point.
What exactly is electronegativity?
Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons
Explain how electronegativity can be used to predict bonding.
It can be determined by what type of bond is used, it normally only applies to Ionic and Covalent bonds.
Why does Hydrogen have a full valence shell if it only has 2 valence electrons and not 8?
The first energy level is full with two electrons, so it only needs one electron to fill its valence shell.
Why is hydrogen " H2" and oxygen "O2" ?
They are found in pairs because they obey the octet rule that way.
What are valence electrons?
Valence electrons are in the outermost shell of an atom, they can be transferred or shared with another atom
define hydrate
a compound with water chemically attached to its ions
what makes up a ionic compound
a metal and a nonmetal
what makes up an ionic compound
a metal and a nonmetal
a formula must have the correct number of positive and negative ions so the charges __
balance
a ___ ____ is the force that holds atoms together in a compound
chemical bond
A ___ ___ is composed of symbols and subscripts indicating the number of atoms of an element in a compound
chemical formula
noble gases are more ___ stable than other elements because they have a complete outer energy level
chemically
Name five or more properties of ionic compounds
form crystals, are hard, brittle, have a high melting and boiling point, conduct electricity but only when they are dissolved in water and formed when metal cations bond with nonmetal anions
use oxidation numbers and their least common multiples to write __
formulas
when an atom ___ an electron, it becomes a negatively charged ion
gains
define oxidation number
how many electrons an atom has gained, lost, or shared to become stable
a __ is a charged particle because it has more or fewer electrons than protons
ion
define binary compound
ionic compounds that contain only two types of monoatomic ions e.g. NaCl
ionic compounds are made of __ and ___
metals, nonmetals
__ molecules are neutral particles formed as a result of sharing electrons
molecules
when writing formulas, remember that the compound is __
neutral
name binary covalent compounds by using ____ to indicate how many atoms of each element are in the compound
prefixes
some elements combine chemically and no longer have the same __ they did before forming a compound
properties
define ionic bond
the force of attraction between opposite charges of the ions
the sum of the charges on the ions in a unit of the compound is ___
zero
