Gchem

Front 1

The geometry or shape of a molecule refers to positions of atoms/electron pairs/both?

Back 1

ONLY positions of atoms

Front 2

An element which can act as an electron acceptor should have a high or low electron affinity? metal or non-metal?

Back 2

high electron affinity, non-metal (like S)

Front 3

Acid vs. Base

Back 3

Acid: Arrhenius- a substance that ionizes in water to produce protons
Bronsted-Lowry- a substance that donates a proton to some other substance
Lewis- electron pair acceptor

Base: Arrhenius- a substance that ionizes in water to produce hydroxide ions
Bronsted-Lowry- a substance that accepts a proton from some suitable donor
Lewis- electron pair donor

Front 4

First ionization energy

Back 4

the energy required to remove an electron from the outer shell of an atom
-low value: when removal of e- yields a complete shell
-high value: when removal of e- disrupts a complete shell

Front 5

Mass Number= ___ + ____

Back 5

protons + neutrons in the nucleus

Front 6

How do you calculate a half life?

Back 6

original amount/final amount=#
2^ what power= #
power= # half-lifes
#half-lifes * # yrs in one half life= # yrs that pass

Front 7

Nucleons

Back 7

Protons & Neutrons

Front 8

Atomic Number

Back 8

# Protons in nucleus

Front 9

Mass Number

Back 9

# Protons + # Neutrons
* sometimes written after name of element

Front 10

Isotopes

Back 10

Differ in numbers of neutrons
Same atomic #

Front 11

A greater value of n (shell number) denotes what?

Back 11

A greater electron energy and average distance from the nucleus

Front 12

First, second, third, and fourth quantum #'s?

Back 12

First/shell quantum # (n): size and energy of orbital
Second/subshell quantum # (l): shape (& energy) of orbital
Third/orbital quantum # (mL): orientation of orbital
Fourth/spin quantum # (mS): electron's intrinsic magnetism, spin of electron in orbital

Front 13

Hund's Rule

Back 13

electrons in the same subshell occupy available orbitals singly, before pairing up

Front 14

Pauli Exclusion Principle

Back 14

no two electrons in the same atom can have the same set of four quantum #'s

Front 15

Can use periodic table to assign electron configurations, BUT beware of the d block whose n is in the d block because...

Back 15

the element has its outermost electrons in the subshell 1 less from the period number

Front 16

Atoms that are at a more stable, lower-energy state when an inner orbital electron is transfered to the outermost orbital:

Back 16

Copper, silver, gold, wants half-filled d
Chromium, molybdenum wants filled d

Front 17

To find electron configuration of ions:

Back 17

For cations: losing 1 or more electrons--move to the left the # of squares equal to the # electrons lost to find the atom w/same config as the ion
For anions: gained electrons, move to the right by # squares equal to number of electrons added in order to find the atom with the same configuration as the ion

Front 18

For transition metals: valence electrons from which subshell get ionized first?

Back 18

s, and only once these are gone do the d ones get ionized as well

Front 19

Ionization

Back 19

Process in which an ion is created from a neutral atom or molecule by adding or removing one or more electrons

Front 20

DIAMAGNETIC

Back 20

All electrons are spin-paired
-diagmagnetic
-repelled from a magnetic field

Front 21

PARAMAGNETIC

Back 21

Not all electrons spin-paired
-attracted into a magnetic field

Front 22

An electron is in its excited state when...

Back 22

it absorbs energy (em radiation or photon) equal to the difference in energy between level its in and current level

Front 23

What is always the amount of energy absorbed or emitted by an electron in moving between energy levels?

Back 23

= to the difference in the energy levels involved in the transition

Front 24

Fluorescence

Back 24

A process in which a compound emits light at one wavelength while being excited by radiation with a shorter wavelength
-observed when photons corresponding to lower-energy transitions are in the visible spectrum

Front 25

What is an excited atom? Is it an ion?

Back 25

an excited atom is NOT an ion, because electrons are not lost or gained
-in an excited atom, electrons jump to higher energy levels within the atom

Front 26

Emission Spectrum

Back 26

-created by passing light emitted by excited atoms through a prism
-an energetic "fingerprint" of the element, because it consists of a unique sequence of BRIGHT lines that correspond to specific energies @ which atom can EMIT photons

Front 27

Absorption Spectrum

Back 27

-an energetic fingerprint of the element, gives a unique sequence of DARK lines that correspond to the specific frequencies and wavelengths at which atoms of the element can ABSORB photons

Front 28

What is a strong nuclear force?

Back 28

-stronger than electrical force between charged particles, because the strong nuclear force must overcome the electrical repulsion between the protons

Front 29

Characteristics of STABLE nuclei

Back 29

-# neutrons is usually equal to or slightly greater than # protons
-as atomic # increases, ratio of # of neutrons to protons increases

Front 30

Radioactivity

Back 30

-characteristic of unstable nuclei, which undergo radioactive decay to make themselves more stable (altering # & ratio of protons & neutrons or just lowering their energy)

Front 31

The nucleus that undergoes decay is called the ____
The resulting, more stable nucleus is known as the ________

Back 31

The nucleus that undergoes decay is called the _parent___
The resulting, more stable nucleus is known as the ___daughter_____

Front 32

3 Types of Radioactive Decay

Back 32

Alpha
Beta
Gamma

Front 33

What is alpha decay?

Back 33

-occurs when a large nucleus wants to become more stable by reducing # of protons & neutrons
alpha= 2 protons and 2 neutrons (same as a Helium nucleus)
-reduces the parent's atomic # by 2 and mass # by 4
MAIN POINT: decreases the number of neutrons and protons in large nucleus, subtracts 4 from mass # and 2 from atomic #

Front 34

What is beta decay?

Back 34

3 types: B- (beta), B+, & Electron Capture
-the transmutation of a neutron into a proton or vice versa through the action of the WEAK NUCLEAR FORCE

Front 35

E photon equation

Back 35

E photon= hf= (hc)/ lambda

Front 36

When the MCAT says "beta decay" without any further qualification, it means...

Back 36

B- decay

Front 37

What is B- decay?

Back 37

When an unstable nucleus contains too MANY neutrons, it may convert a neutron into a proton & an electron (a B- particle) is EJECTED
-mass # is same, atomic # of the daughter nucleus is 1 greater than the radioactive parent nucleus
MAIN POINT: decreases # neutrons, increases # protons, adds 1 to atomic #

Front 38

What is B+ decay?

Back 38

-When an unstable nucleus contains too FEW neutrons, it converts a proton into a neutron & a positron, which is ejected
MAIN POINT: increases # neutrons, decreases # protons, subtracts 1 from atomic #

Front 39

What is a positron?

Back 39

Emitted in B+ decay, it is the electron's antiparticle
-identical to electron BUT charge is +1
-atomic # of daughter is 1 less than parent, but mass # doesn't change

Front 40

What is electron capture?

Back 40

-to increase its # of neutrons, an unstable nucleus captures an electron from the closest electron shell & uses it in the conversion of a proton into a neutron (show electron on right-hand side of equation)
-RESULT: atomic number reduced by 1, and mass # doesn't change (like in B+ decay)
MAIN PT: increases # neutrons, decreases # protons, subtracts 1 from atomic number

Front 41

What is gamma decay?

Back 41

An expulsion of energy in the form of gamma photons (photons of em radiation)
-MAIN PT: brings an excited nucleus to a lower energy state, doesn't change identity of nucleus (neither mass nor atomic #)