chemical bonding Flashcards
how are chemical compounds formed?
they form when atoms are bonded together
- have low potential energy when atoms are bonded
endothermic
breaking a chemical bond
absorbs energy = cooler surroundings
exothermic
forming a chemical bond
release energy = warmer surroundings
low potential energy
compounds with strong stable bonds = dont release much energy when broken
high potential energy
compounds with weak + unstable bonds = release moore energy
what are the 2 kinds of compounds?
ionic (nonmetal + metal, cation +anion)
covalent
ionic compounds
high + boiling points, dissolves in water, conducts electricity in solution
covalent
low melting point + boiling point, DO NOT CONDUCT ELECTRICITY NOR DISSOLVE IN WATER
What is a chemical bond?
formed when valance electrons are transferred (ionic) or shared (covalent) between atoms
What is polarity?
distribution of electrons
polar = asymmetrical
non-polar = symmetrical
what happens when an atom gains an electron?
radius increases because electrons are further away from the nucleus
what happens when an atom loses an electron?
radius decreases = electrons closer to the nucleus
how do atoms become stable?
by ionic bonds donating electrons and covalent bonds sharing electrons
when are atoms stable
when they have a full valance shell (8 electrons)
exception: H only needs 2
electronegativity
atoms attractions to electrons
0.0-0.4
non polar covalent
0.4-1.7
polar covalent
higher than 1.7
ionic
intermolecular forces
attractive forces that increase between the molecules of substances (elements + compounds) and responsible for physical + chemical properties
hydrogen bonds
strong intermolecular forces
FON means..
fluorine, oxygen, nitrogen
substances with hydrogen bonds have…
high + boiling melting points
dipole dipole
type of intermolecular force
positive + negative molecule
do covalents share or donate?
share
do ionics share or donate?
donate
when bonds are formed they..
have lower potential energy because formed bonds released energy
what are the forces between atoms that create chemical bonds?
due to attractions between protons + electrons
polars are dipole dipole because..
they are asymmetrical due to unequal electrical charges (opposite)
why are metallic good conductors of electricity?
due tot its valance electrons being stationary (they move freely)
non polar COVALENTS are….
insoluble in water + low boiling points due to nonmetals
