Chapter 5 Flashcards
what are the most prevalent type of elements in nature?
compound
why are noble gases usually found by itself in nature?
they are stable because they have an octet
octet rule
tendency for atoms to share/transfer electrons to obtain 8 valence electrons
what type of elements are an exception to the octet rule?
transition elements
ions
electrical charge from gain/loss of electrons
what charge do metals have and why?
positive, they have low ionization energies (lose electrons easily)
ionic charge
difference between number of protons and number of electrons on upper right hand corner of symbol
cations
positively charged ions of metals
why are metal ions smaller than metal atoms?
because they lose electrons and its’ energy level decreases
anions
negatively charged ions of nonmetals
what ending does anions have?
-ide
do nonmetals gain or lose electrons and why?
they gain electrons, they have high ionization
What are the charges of elements in group:
1A(1) ,2A(2) ,3A(3) ,7A(17) ,6A(16) ,5A(15)
group 1- 1+ group 2- 2+ group 3- 3+ group 17- 1- group 16- 2- group 5- 3-
what are the exceptions of the ionic charge and group number pattern?
transition elements, and group 4A(14) do not typically form ions (exception Sn, and Pb)
Ionic compounds
compound of positive and negative ions held together by ionic bonds (typically metal and nonmetal)
ionic bonds
attraction between positively charged metal ions and negatively charged nonmetal ions
are the physical and chemical properties of ionic compounds similar to its original elements?
no
ionic compounds generally have ___melting points and are ____ at room temperature
high melting points and
solid at room temperature
chemical formula
represents symbols and subscripts in the lowest whole number ratio of the atoms or ions
what is the order of writing a chemical formula?
cations first, then anions
How do you name an ionic formula?
metal ion first then nonmetal ion (space in between both)
why is it hard to determine the charge of transition elements?
because they can lose s and d electrons which allows them to form 2 or more positive ions
which group has the same rule as transition elements when it comes to naming them? and what are the exceptions?
Groups 4A (14) and 5A (15) exceptions: Zn2+, Ag+, Cd2+
how do you name transition elements?
you use roman numerals that represents its ionic charge in parentheses after the cations
what elements have a variable change?
Any element that can form 2 or more positive ions.
ex: transition elements and group 14,15
polyatomic ions
group of covalent bonded atoms that has an overall ionic charge
what makes up most of polyatomic ions?
a nonmetal bonded to an oxygen
what do polyatomic ions generally end in?
-ate
when does a polyatomic ion end in -ite
if it has one less oxygen than -ate
which group can form 4 different polyatomic ions with oxygen?
group 7A
when do you add the prefix “per-“
when it has one more oxygen than the “ate” form
when do you add the prefix “hypo-“,
when it has one less oxygen than the “-ite” form
List the prefixes and suffixes in order from most oxygen to least.
per- -ate
-ate
-ite
hypo- -ate
How do you name polyatomic ions?
positive ion + polyatomic ion
Covalent compound
two nonmetals share electrons
why can’t nonmetals share electrons?
they have high ionization energies
covalent bonds
nonmetals share electrons
molecule
2 or more atoms that share electrons, AKA covalent bond
lewis dot structure/ electron dot formula
shows valence electrons in covalent molecule
bonding pair
the electrons that are being shared
lone pairs
the electrons that aren’t being bonded
how are bonding pairs represented on the LDS/EDF?
2 dots or a line
Which elements are exceptions to the octet rule? (can form more than 8 electrons?) how many can they form?
P,S,Cl,Br,I
can form 10,12,14 valence electrons
double bond
2 pairs of electrons shared
triple bond
3 pairs of electrons shared
Which elements will not form double or triple bonds?
hydrogen and halogens
why do double and triple bonds form?
when there aren’t enough valence electrons to complete an octet, so lone pairs are shared
resonance structures
all possible ways to write the electron dot formula
how do you name covalent bonds?
using full name of first element+ second element’s first syllabi+ “-ide”
what prefixes can you use in front of elements?
mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca
electronegativity
ability of atom to attract shared electrons in a bond, it determines if electrons are shared evenly or unevenly
which element has the highest electronegativity?
Flourine
which generally has a higher electronegativity?
nonmetals
transitions have ___ electronegativity
low
what is the electronegativity of noble gases?
they dont have any elevtronegativity values
nonpolar covalent bond
electrons shared equally, atoms have identical/similiar electronegativity
polar covalent bond
electrons arent shared equally because there is an electronegativity difference
dipole
polar covalent bond that has a slight charge on each atom
if a polar covalent bond has an atom with higher electronegativity the charge is
partially negative
if a polar covalent bond has an atom with lower electronegativity the charge is
partially positive
what is the acceptable electronegativity difference for a atom to be considered a nonpolar covalent bond?
0.4 or less
what is the acceptable electronegativity difference for a atom to be considered a polar covalent bond?
0.5-1.8
the polarity of a bond increases as the electronegativity difference____.
increases
what is the acceptable electronegativity difference for a atom to be considered an ionic bond?
1.9 or higher
valence shell electron pair repulsion(VSEPR) theory?
a theory that predicts the shape of a molecule by placing electron pairs on a central atom as far apart as possible to minimize the mutual repulsion of the electrons
linear # of electron groups, bonded atoms and bond angle
shape of a molecule, 2 electron groups and 2 bonded atoms
bond angle-180
trigonal planar
shape of a molecule, 3 electron groups, 3 bonded atoms, bond angle-120
bent
shape of a molecule, 4 or 3 electron groups, 2 bonded atoms
bond angle-120
tetrahedral
4 atoms attached to 4 electron groups
bond angle- 109
how does a tetrahedral bond?
at the corner of central atoms
trigonal pyramidal
4 electron groups, 3 bonds (1 lone pair)
bond angle- 109
nonpolar molecules
all bond are nonpolar OR when polar bonds/dipoles cancel each other because of symmetrical arrangement
polar molecules
one end of molecule is more negatively charged than another end
when does polarity occur
when polar bonds/dipoles dont cancel out
when are molecules usually nonpolar?
when a polar molecule with 3 or more atoms contain a lone pair
relationship of low attractive force and melting/boiling point
low attractive force= low melting/boiling points
relationship of high attractive force and melting/boiling point
high melting and boiling points
