chemistry all year flashcards

What are valence electrons

electrons on teh outer most layer of the energy levela

What does the period law say?

at regular but varying intervals, elements show a general repeating of properties due to their electron configuration

Important periodic Groups

• alkali metals

• alkali earth metals

• halogens

• noble gasses

• transition metals

What are monotonic atoms?

atoms existing as a single atom in nature, being happy alone

What are diatomic atoms?

atoms that never exist alone in nature, are always found together

ways to memorise: BrINClHOF or 7 up

What are characteristics of metals?

• good conductors of electricity and heat

• maleable

  • can be hammered to thin sheets

• ductile

  • able to be a wire

• have lusture/shine

• tend to loose electrons

• cations

What are characteristics of non metals?

• poor conductors

• brittle

• tend to gain electrons

• anions

What are characteristics of Alkali Metals?

• Li, Na, K, Rb, Cs, Fr

• highly reactive(especially with water)

• always found combined

What are characteristics of Transition Metals?

• variable ionic charges due to the electron configuration

• widely used

• have many different properties

What are characteristics of Halogens?

• most reactive non metals

• show trends in colour and phase at stp(standard temperature and Pressure)

• only group with solid, livid and gas

What are characteristics of Noble gasses?

• very unreactive

• non metals

What is effective nuclear charge?

the charge that valence electrons feel from the nucleus

Why is the nuclear charge always positive?

bc it only includes protons and neutrons

What is the equation of the effective nuclear charge?

Z_eff=Z-S

Z_eff=effective nuclear charge

Z=nuclear charge

S=number of inner electrons

How do scientists standardise the Atomic Radius of Elements?

by measuring the distance between the nuclei of two identical atoms bonded together and diving it by 2

What units are used to measure the Atomic Radius?

Picometers(1 × 10^-12m)

What are there periodic trends of Atomic radii?

• generally decreases from left to right along the period as the Z_effis larger and the electrons feel the pull of the nucleus more

• some exceptions exists

• Generally increases going down a group as energy levels are added and take up more space

What is a Ion?

a charged particle that either lost or gained electrons

What is are two types of ions?

cations or anions

What is a cation?

a positively charged ions(looses electrons)

What is a anion?

a negatively charged ion(gains electrons)

Why do atoms/elements want to gain or loose electrons?

to create a perfect octet, full outer sub shell configuration

What is Ionisation Energy?

the energy required to remove one electron from an atom

What is the measurement used in ionisation energy

kJ/mol

What are the period trends of ionisation energy and why are they like that?

• when moving across the period to increases meaning its harder to remove electrons from the atom bc of Z_eff

• when moving down a group it decreases as the inside energy levels are blocking the Z(nuclear charge) of affecting the valence electrons as much

What is electron affinity?

the energy released when atoms turn into ions

What are the period trends of electron affinity?

• generally across the period it increases

• generally down a group it decreases

What is the Ionic Radii?

• the radius of a crystal lattice(requires element to be in solid form)

• usually x ray crystallography is used to determine of the radius

Trends of Ionic Radii?

• cations turn a lot smaller than the original atom

• anion turns a lot bigger than the original atom

What is Electronegativity?

the ability of an atom to attract electrons in a compound

What are the period trends of Electronegativity and why?

• increases across the period during to a increase in Z_eff

• generally decreases going down a group bc of Z_eff

• noble gasses do not have electronegativity

What is metallic Character?

how much a element behaves like a metal

What are the period trends of Metallic Character?

• generally increases going down a group

• generally decreases going across the period

What are the two types of substances?

elements and compounds

What is electrostatic attraction?

the attraction between two ions

How do you name an anion?

ide

How do you name a cation?

xy ion

do you draw the 8 valence electrons on a lewis dot diagram on an cation?

no

do you draw the 8 valence electrons on a lewis dot diagram on an anion?

yes

What are properties of Ionic compounds?

• neutral charge

• crystalline at room temperature

• known to have high melting and boiling point

• brittle

• can conduct electricity when dissociated

• always in liquid or aqueous phase

What are all ionic compound called

salts

What is dissociation?

when ionic compounds split apart fully in water

What are characteristics of metallic compounds?

• atoms loose electrons

• the lost valence electrons are floating around in the area

• malleable

• ductile

• compact and organised which makes them lustre

What are the loose electrons called in a metallic bond?

sea of electrons

between where is the attraction in a metallic compound?

cations and electrons

What happens in covalent bonding?

sharing valence electrons to form a bond

What is a Molecular Compound?

neutral atoms joined by covalent bonds

What is a Polar Covalent bond?

an asymmetric molecule with a slight charge on each end because the electrons are shared slightly unequally bc of electron negativity

What is a Network Solids?

are compounds in which atoms are bonded in a continues network throughout a material

What are Allotropes?

some elements, different structures and therefore properties

What does IMF stand for?

Inter Molecular Forces

What is IMF?

forces of attraction between molecules

Properties of Covalent Bonds

• low melting and boiling points bc the IMF is weaker

What are the three types of intermolecular forces?

1. permanent dipole dipole

2. hydrogen bonds

3. van der Waals

Permanent dipole dipole characteristics

• strongest of all intermolecular forces

• force between slightly positive and slightly negative parts in compounds

• ex. hydrogen Chloride

Hydrogen bonds

• type of dipole dipole inter molecular forces

• only for HN or HO or HF because these are especially strong

• only 5% of an actual bond

Van der Waals

• induced dipole-dipole interactions bc of electron movement in shells

What does Mono mean?

one

What is di short for?

two

What is tri short for?

three

What is tetra short for?

four(remember by tetris always having 4 blocks)

What is pent short for?

five

What is hexa short for?

6

What does a Chemical formula show?

tell us type and number of each element bonded together in a compound

What is the correct term for ‘=’ in a chemical equation?

yield

What does the law of conservation say?

matter can neither be created or destroyed

What are tips and tricks when balancing equations?

• if there are an odd number of atoms on one side, multiply everything by two

• leave H and O for last

• do H before O

What are the 5 types of Reactions?

• combustion reaction

• synthesis reaction

• decomposition reaction

• single replacement

• double replacement

Combustion reaction

C_xH_y + O₂ → CO₂ + H₂O

Synthesis Reaction

element + element → compound

Decomposition Reaction

Compound → element + element

Single replacement reaction

X + AB → A(or B) + XB(or A)

double replacement Reaction

XY + AB → XB + AY

Methane

CH₄

ammonium

NH₄⁺

acetate

CH₃COO^-

carbonate

CO^-2₃

Bicarbonate

HCO₃^-

Hydroxide

OH^-

Permanganate

MnO₄^-

Chlorate

ClO₃^-

Sulfate

SO₄^-2

Nitrate

NO₃^-

Phosphate

PO₄^-3