General Chemistry Flashcards
Atomic number
number of protons, if this changes you have a new element
Mass number
total mass of protons plus neutrons
subtract atomic number from mass number to find the number of neutrons in a molecule
What are isotopes used for?
track chemical reactions
How to name elements with more than one cation (transition metals)
use roman numerals
use -ous prefix for smaller charge and -ic prefix for greater charge
Naming oxyanions
hypo- -ite (2 less)
-ite (1 less)
-ate (normal)
per- -ate (more)
Pauli Exclusion Principle
no two electrons in an atom can have exactly the same four quantum numbers
Ranking of orbitals, shells and subshells
Shells are periods (n=1, 2, 3 …)
Subshells are s,p,d,f (n=1 only has the s subshell)
Orbitals are within the subshells and can hold 2 electrons (s can have 1 orbital, p can have 3 orbitals)
Aufbau principle
electrons fill lower orbitals first
Hund’s rule
fill orbitals half full first
(everyone wants own seat on the bus)
Group 1 elements
alkali metals
highly reactive
good cations
Group 2 elements
alkaline earth metals
Group 6 elements
chalogens
Group 7 elements
halogens
often found as diatomic molecules to form complete valence shell
Trends with Zeff
increases across periodic table (more protons with no new shell electrons)
decreases down periodic table (more protons but also more shell electrons to block Zeff)
Trends with radius
decreases across periodic table since Zeff is increasing
increases down periodic table
Trends with electronegativity
increases across periodic table
decreases down periodic table
same as Zeff
Are anions bigger or smaller than neutral atom?
bigger
more electrons = more electrostatic repulsion
Are cations bigger or smaller than neutral atom?
smaller
less electrons = less repulsion and greater Zeff
Ionization energy
amount of energy to remove electron from atoms
first electron always the easiest to remove
Which bonds can lead to H-bonding?
-FH -OH and -NH bonds
especially electronegative bonds
Combustion reaction
a compound burns in the presence of oxygen
highly exothermic
Does a reaction with a +H make the surrounding area warmer or colder?
+H indicates an endothermic reaction
takes heat from the environment to drive reaction
makes the surrounding area colder
Does increasing temperature speed up all reactions?
No. Only speeds up endothermic reactions where heat acts like another reactant
Neutralization reaction
Acid + Base –> H2O + Salt