DAT Bootcamp: General Chemistry

High-Yield Flashcards

What is an element?

the PUREST form of a substance that CANNOT be broken down further

What is an atom?

the smallest particle or unit of an element

What is an ion?

a charged atom or molecule, formed by adding or removing electrons

What is a molecule?

a single structure made up of two or more atoms (same or different atoms)

What is a compound?

a structure made up of two more DIFFERENT elements

What is the relationship between molecules and compounds?

all compounds are molecules, but not all molecules are compounds

What is homogeneous mixture?

a mixture that is UNIFORM in composition and appears the same throughout (aka solutions)

What is a heterogeneous mixture?

a mixture that is NOT UNIFORM in composition

What type of mixture is a solution?

a homogeneous mixture

What type of mixture is a mixed coffee?

a homogeneous mixture

What type of mixture is a salad?

a heterogenous mixture

What is matter?

anything that takes up space and has mass

What are the phases of matter?

• solids

• liquids

• gasses

• plasma

What is a solid?

a phase of matter that is rigid and has a definite space

What is a liquid?

a phase of matter that flows and takes the shape of its container

What is a gas?

a phase of matter that takes the shape and volume of its container

What is plasma?

a phase of matter that exists in a gaseous state and contains electrically charged particles (at very high temperatures)

What is mass?

a measure of the amount of matter in an object (same on all planets)

What is weight?

the force that gravity exerts on an object (different on all planets)

How is weight represented mathematically?

w=mg

What is the Law of Conservation of Matter?

a scientific law that states matter cannot be created or destroyed

What are physical properties?

properties that DO NOT alter the composition of a substance

What is a physical change?

a change that DOES NOT alter the chemical composition of a substance

What are chemical properties?

properties that alter the composition of a substance

What is a chemical change?

a change that results in alteration to a substance’s chemical composition

What types of properties are density, color, and melting point?

physical properties

What types of properties are separating a mixture, flammability, toxicity, and reactivity?

chemical properties?

What is an intensive property?

a physical property that DOES NOT depend on the amount of substance present

What is an extensive property?

a physical property that depends on the amount of substance present

What are intensive properties used for?

identification of a substance

What are extensive properties used for?

quantification

Are density, temperature, and melting point intensive or extensive properties?

intensive properties

Are mass and volume intensive or extensive properties?

extensive properties

What are SI Units?

standardized units used in chemistry and science

What is the SI unit for length?

meter (m)

What is the SI unit for time?

second (s)

What is the SI unit for temperature?

kelvin (K)

What is the SI unit for amount of substance?

mole (mol)

What is the SI unit for electric current?

ampere (amp)

What is the SI unit for luminous intensity?

candela (Cd)

What is the SI unit for mass?

kilogram (kg)

What is dimensional analysis?

a process used to convert from one set of units to another

What is the general formula for dimensional analysis?

How to fill electron orbitals?

based on the s, p, d, and f blocks

Hund's Rule

states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals

Aufbau Principle

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

The electrons whose orbitals are __________________ away from the nucleus (those with the largest principle quantum number, n) are the atom's valence electrons.

furthest

The ______________ electrons are the highest energy elections and the ones that play a role in chemical reactions.

valence

For elements in the _____ block, the ___ shell electrons are also valence electrons.

d

The higher an electron's principle quantum number (n)...

- the further the distance from the nucleus

- the higher the energy

- the higher the reactivity

What are the five exceptions in electron configuration?

Chromium [Ar] 4s¹ 3d⁵

Molybdenum [Kr] 5s¹ 4d⁵

Cu [Ar] 4s¹ 3d10

Ag [Kr] 5s¹ 4d10

Au [Xe] 6s¹ 4f14 5d10

Cr & Mo move an electron down in order to...

get their electrons unpaired

Cu, Ag, Au move an electron down in order to...

to have it in a lower energy state and be more stable

Paramagnetic

have an unpaired electron

Paramagnetic substances are ______________ to magnets.

attracted

Diamagnetic

all electrons are paired

Diamagnetic substances are slightly ___________ by magnets.

repelled

If an element has an _______ number of electrons then it is paramagnetic.

ODD

If an element has an _________ number of electrons, then it is paramagnetic OR diamagnetic. You have to use the energy diagram to figure it out.

EVEN

Energy of a Photon

hf = hc÷λ

The energy of a photon is directly related to its ______________.

frequency

The energy of a photon is inversely proportional to its ____________.

wavelength

As the energy of a photon increases, the frequency will ________________ and the wavelength will ________________.

increase; decrease

Frequency =

1/λ

N₂ is

diamagnetic

O₂ is

paramagnetic

Octet Rule

refers to the tendency of atoms to prefer to have eight electrons in the valence shell, so that they can behave like noble gases

When atoms gain an electron they become ___________ charged.

negatively

When atoms lose an electron, they become ___________ charged.

positively

Compounds

are molecules comprised of two or more different elements bonded together

Metals v. Nonmetals

helps to determine if an ionic or a molecular compound is formed

Ionic Compounds

metal + non-metal --> through ionic bonds

(exceptions being the polyatomic ions)

Molecular Compounds

non-metal + non-metal --> through covalent bonding

_____________ determines if the sharing between electrons is equal or unequal.

Electronegativity

___________ Covalent Bonds are molecular compounds with an uneven sharing of electrons caused by a significant different in electronegativity.

Polar

They have partial positive or negative charges

______________ Covalent Bonds occur when nonmetal atoms do not have a significant electronegativity difference between them.

Nonpolar

They do not have partial charges.

Lattice Energy

the energy required to completely separate an ionic compound's cations from its anions

The larger the charges =

the larger the lattice energy

The shorter the bond distance =

the larger the lattice energy

Hydrogen only wants ______ electrons.

2

Beryllium only wants ______ electrons.

4

Boron and Aluminum only want ______ electrons.

6

_________ row and lower can have more than 8 electrons if needed.

Third

Each triple bond is one _____ and two _____ bonds.

σ; π

Each single bond is one _____ bond.

σ

Each double bond is one _____ and one ________ bond.

σ; π

Formal Charge =

(valence electrons) - (one for each dot) - (one for each bond)

A __________ is a column and elements within here have similar properties.

group

A ______________ is a row and elements within here do not necessarily have similar properties.

period

Group 1 = ________ Metals

Alkali

low ionization energies because they want to lose an electron to feel like a noble gas; it is a lot easier for them to shift to the right than the left

- explosive with water

- form ionic compounds

What is the common formula of alkali metals?

M(s) + H₂O(l) --> MOH (aq) + 1/2H₂(g)

- extremely exothermic

Group 2 = ___________ ____________ Metals

Alkaline Earth Metals

- low ionization energies (but not as low as gorup 1)

- Do react with H₂O, but not as violently as group 1

- Generally get more reactive as you go down the group.

Group 7A/17 = ______________

Halogens

- High electronegativities/electron affinities

- They are easily reduced and want to have an extra electron

- Highly reactive with metals

- They are only one valence electron away from full octet

Group 8A/18 = ______________

Noble Gases

- they are inert

D block = _____________ Metals

Transition

- often form brightly colored compounds due to the way that d-orbitals allow electrons to absorb colored light and be promoted to higher energy levels

- multiple oxidation states (ie: iron)

Group 6A = ____________ Group or the Chalcogens

- two forms of molecular oxygen O₂ and O₃.

- O₂ is a good oxidizing agent (oxidant), but O₃ is an even better oxidizing agent

- Metals like to react with oxgen to form metal oxides

Atomic Radius

the distance from its nucleus to the outside of its outermost orbitals

Bond Length =

atomic radius of first element + atomic radius of second element

An increase in the number of energy shells (n) -->

an increase in size

As the effective nuclear charge increases --->

the size of the element decreases