CH 1-4 gen chem

where is a proton located

in the nucleus

what is the charge of a proton

+1

what is the mass of a proton

1 amu

what symbol represents the number of protons in an element

z, atomic number

what does the number of protons do for an element

it identifies it since atomic number is unique to each element

what is an element

a substance that contains only ONE type of atom.

what are isotopes

atoms with the same number of protons but different number of neutrons

what is the charge of a neutron

0

what symbol represents mass number

A, it is written on top of Z

what is mass number

the total number of protons and neutrons in a nucleus

how are isotopes written

the element is followed with a dash and the mass number

an example is carbon-12 and carbon-13

where are electrons located

outside the nucleus

what are valence elctrons

outermost shells

what is special about valence elctrons

they determine reactivity and participate in bonding to fill their outermost shell

what does losing electrons cause

a gain of positive charge

what does gaining electrons cause

a gain of negative charge

cation ion

positive ion

think cats are good- positive

anion

a negative ion

mass of neutron

1 amu

mass and charge of electrons

-1 charge

negligible mass

atomic mass vs atomic weight

Atomic WEIGHT is a WEIGHTED average of naturally occuring isotopes of that element. It is consistent and the one written on the periodic table.

Atomic MASS is the weight of a single atom/ isotope and it varies depending on which isotope you weigh. Is nearly equal to mass number

1 mole

6.02 x 10^23 particles

what is an atomic mass unit (amu)

1/12 the mass of a carbon-12 atom

what does amu represent

the mass of the average atom of the element and the mass of one mole of the element in grams

what is Rutherford's model

dense positively charged nucleus with electrons outside

what is Planck's idea

energy from electromagnetic radiation is emitted in discreet bundles called quanta

what is Planck's constant

6.626 x 10^-34 Js

what is the energy equation involving wavelength and frequency

E=hf=hc/lambda

what is Bohr's model

depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus

what is true about the energy level of electrons and distance

the farther out an electron is from the nucleus, the greater its energy

the closer an electron is to the nucleus, the less its energy

what is true about energy and the quantum number

they are proportional, they increase and decrease together

what synonym is helpful for electron behavior

AHED:

electron Absorb light

have a Higher potential

they are Excited

and gain Distance from the nucleus

what is true about the absorption spectrum

it is quantized- not continuous, rather photons emitted at certain wavelengths

it is unique to each element and can be used to identify

how do electrons go to higher energy levels

The atomic absorption spectrum of an element is unique; for an electron to jump from a lower energy level to a higher one, it must absorb an amount of energy precisely equal to the energy difference

between the two levels.

When electrons return from the excited state to the ground state, they emit an amount of energy that is exactly equal to the energy difference between the two levels; every element has a characteristic atomic emission spectrum, and sometimes the electromagnetic

energy emitted corresponds to a frequency in the visible light range.

What is the quantum mechanical model

electrons do not travel in defined orbits but rather are localized in orbitals which are a region of

space around the nucleus

Heisenberg uncertainty principle

it is impossible to know exactly both the velocity and the position of a particle at the same time

Pauli Exclusion Principle

no two electrons in the same atom can have the same set of four quantum numbers

electrons in the same orbital must have opposite spins

what is true about energy differences between energy levels

also rhydberg equation and what does it show us

what is the hydrogen emission series

as you go further out, energy differences decrease

going from n=2 to n=1 releases more energy than n=9 and n=8

higher energy levels have higher energy, but the energy difference and therefore energy released by travel is less the higher you go

The Rydberg equation quantifies the wavelengths of spectral lines of hydrogen, illustrating how energy transitions between levels correspond to electromagnetic radiation: 1/wavelength= R (1/nf squared- 1/nisquared)

The hydrogen emission series illustrates the specific wavelengths of light emitted when electrons transition from higher to lower energy levels, resulting in distinct spectral lines that correspond to various colors. Lyman falls to n=1, balmer falls to n=2, paschen falls to n=3 (LBP, lets be proud)

What are quantum numbers

n, l, ml, ms

principal quantum number symbol and what it represents and the possible values

n

energy level/distance from nucleus

1 and greater, whole number integers

angular/azumthal quantum number symbol and what it represents and the possible values

l

0 up to n-1

corresponds to the subshells

correspond angular quantum numbers to shapes

0=s, sphere

1=p, dumbell

2=d, 2 dumbells

3=f, 3 dumbbells

what is true about energy of subshells

increase as value increases within the same energy level

however, we know from afbau that 6s is higher than 5d for instance

magentic quantum number symbol and what is represents and possible values

m1

represents number of orbitals within subshells

ranges from - angular quantum to positive angular quantum

ex: angular quantum equals 2, this corresponds to sublevel of d, and the magnetic quantum can be -2, -1, 0,1,2

these are five values so there are five orbtials in the d- sublevel

spin quantum number symbol and what it represents and its possible values

ms

the direction of the electron (+ is up and - is down)

possible values of -1/2 and +1/2

each orbital has two electrons maximum

What is the Afbau principle

An electron occupies the lowest-energy orbital that can receive it

Draw out Afbau principle graphic

fill out periodic table with energy levels and sublevel letters

practice electron figurations both full and abbreviated and understand the difference

for abbreviated you start from the nearest previous noble gas and continue from there

how does adding or subtracting electrons change electron configuration

when electrons are added, there is a negative charge gained

when electrons are removed (from outermost level), there is a positive charge gained

ex: Fe3+ has lost 3 electrons so its configuration must be adjusted accordingly

Hund's rule

electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible

put one electron in each orbital before you double up

what are the exceptions to Hund's rule

Copper and Chromium and elements in that GROUP

how do exceptions to Hund's rule behave

also.. how many orbitals does each sub level hold? and how many electrons does each sublevel hold?

one electron is taken from highest s orbital and given to highest d shell

what does Hund's rule confer for an atom

low energy and high stability

diamagnetic

All electrons are paired; slightly repelled by a magnetic field.

think: di=2. 2 is a crowd, repels more people

paramagnetic

unpaired electrons, attracted to magnetic field

attracted: think parasocial relationship

what is a period on the periodic table

a horizontal row

what is a group on the periodic table

a vertical column

What do elements in the same group have in common

the same number of valence electrons

what does having the same number of valence electrons do

means elements have similar properties and reactivity

what do elements in the same period have in common

same number of electron shells

how is the current periodic table arranged

it is arranged by increasing atomic number

identify and label the different groups of elements on the periodic table (metals, nonmetals, metalloids, transition metals)

aluminum is a metal, so staircase except aluminum

properties of metals

Malleable, Ductile and Good Conductors of Heat and Electricity, High MP and Density

what do transition metals commonly have

two or more oxidation states

colors

what is true about metals and electrons

they tend to give up electrons

what is true about non metals and electrons

they tend to hold on and want to gain

what is Zeff

effective nuclear charge

what is effective nuclear charge and its equation

The electrostatic attraction between the valence shell electrons and the nucleus. A measure of net positive charge experienced by the outermost electrons

It can be calculated using the equation: Z_eff = Z - S, where Z is the atomic number and S is the shielding constant.

what is the periodic table trend for effective nuclear charge

increases across a period

unchanged going down a group because The nuclear charge does in fact increase down a group but the shielding effects of additional electrons counters the attractive force. Therefore, effective nuclear charge is largely unaffected.

what is the periodic table trend of atomic radius

decreases across a period

increases down a group

what is the periodic table trend for ionization energy

what is ionization energy

energy required to remove an electron from a gaseous species

increases across a period

decreases down a group

what is important to note about ionization energy

subsequent ie is always higher than the previous value

what is the periodic table trend for electron affinity

what is electron affinity

what does high or low electron affinity

electron affinity is the energy releases when an electron is gained

it varies with Zeff

• High electron affinity = the atom really wants an extra electron. It releases a lot of energy when it grabs one (very negative value).

  • Example: Cl has EA ≈ –349 kJ/mol → it strongly attracts another electron to complete its octet.

• Low electron affinity = the atom doesn’t really care about gaining an electron (small negative or even positive value).

  • Example: Noble gases have positive EA → it actually costs energy to force an extra electron in, since their shells are already full.

if reported as positive values, assume exothermic and larger one has greater has EA (review this tho)

what is important to note about electron affinity

it is exothermic so the delta H rxn is negative but the value is reported as positive

what is true about electron affinity trend

it is zero for noble gases

what is eletronegativity and what is the trend

it is the attraction to electrons in a bond

increases across, decreases down

scale of electronegativity values

Pauling scale

0.7 cesium to 4.0 fluorine

what is true about electronegativity trend

first 3 noble gases are zero

what is the octet rule

Atoms tend to gain, lose or share electrons in order to have a full set of valance electrons (8 valence electrons)

what are the exceptions to the octet rule

(stable with 2 electrons),

helium (2), lithium (2), beryllium (4), and boron (6).

Any element in period 3 and greater can hold more

than 8 electrons, including phosphorus (10), sulfur (12), chlorine (14), and many more

what are the two types of bonds

ionic and covalent

what does an ionic bond entail

a transfer of electrons usually from metal to nonmetal

the resulting electrostatic force holds them together

what do ionic compounds exist as

lattice structures

what does a covalent bond entail

sharing electrons usually between nonmetals

what are the two types of covalent bonds

nonpolar covalent and polar covalent

what makes a covalent bond polar

unequal sharing of electrons

what makes a covalent bond nonpolar

equal sharing of electrons

what is a good way to remember covalent and noncovalent bonds

PUNE

polar unequal, nonpolar equal

electronegativity different of ionic bonds

greater than 1.7

physical properties of ionic compounds

High melting points and conduct electricity when molten or in solution

dissolve in water and other polar solvents

properties of covalent compounds

low melting point, low boiling point, never conducts electricity

bond order meaning

number of shared electron pairs between two atoms

single bond: bond order of 1

double bond: bond order of 2

triple bond: bond order of 3

bond length

the average distance between the nuclei of two bonded atoms

relationship of bond length and bond order

the greater the bond order, the shorter the bond length

bond energy trend (lowest to highest)

single, double, triple

seven diatomic molecules and what to note about them

HONClBrIF

nonpolar bonds, same atom so exact same electronegativity

what is a dipole moment and what is the formula

measure of bond polarity

p=qd (d is for distance and q is magnitiude of charge)

draw out notation for partial positive and partial negative charge

coordinate covalent bond

a covalent bond in which one atom contributes both bonding electrons