Week One Flashcards
Atom
Chemical species with a central positively charged nucleus surrounded by negatively charged electrons
Free Atoms
Usually unstable
Molecules
Atoms with definite structure held together by chemical bonds
Molecules- electrical
Electrically neutral therefore uncharged
Covalent bonds
Sharing electrons between neighbouring atoms
Ions
Species that are either positively or negatively charged
Cations
Positively charged
Anions
Negatively charged
Compounds
Substances containing one or more molecules
Law of conservation of mass
No gain or loss occurs in chemical reactions, mass is conserved
Law of Definite proportions
In chemical compounds, elements are always combined in the same proportion by mass
Law of multiple proportion
When 2 elements form one or more compound, the different masses of one element that combine with the same mass of the other element are in ratio of small whole numbers
Daltons Atomic Theory
Matter consists of particles
Atoms are indestructible
Atoms of different elements differ in mass and properties
F block elements
Bottom two rows of periodic table
D block elements
Groups 3-12
S block elements
Groups 1-2
P block elements
Groups 13-18
Metals - properties
Good conductors of heat and electricity
Malleable
Ductile
Metallic lustre
Nonmetals - properties
Poor conductors of heat and electric Not malleable Not ductile No metallic lustre Majority are gases at room temp
Metalliods - properties
Tend to be semi conductors
Excited state of electrons
Electron lies further from the nucleus, can be promoted to this state by absorption of energy
Redox reactions
Reactions in which one or more electrons are transferred between chemical species
Ground state
Lowest energy arrangement of electrons in the orbital
Pure substances
Have distinct composition and properties
Homogenous Mixtures
Can be solutions, consistent throughout, can’t distinguish individual regions
Heterogeneous mixtures
Composition varies through, consists of two or more identifiable regions
Solids
Ordered arrangements, particles close together, low temp high pressure
Liquid
Disordered wit particles free to move while remaining in close contact (intermediate temp and pressure)
Gas
Total disorder, much empty space, intermolecular forces broken (high temp low pressure)
Physical change
Reversible
Chemical change
Irreversible
Chemical property
Ability to undergo chemical change
Physical property
Involves change in form but not chemical identity
Isotopes
Same number of protons and electrons but different number of neutrons so different mass number
Periods
Horizontal rows
Groups
Vertical rows
0 degrees
273.15 kelvin
Exact numbers
Come from defined values or from counting objects
Imexact numbers
Comes from measurement as there are always limitations
Percentage uncertainty
(Absolute uncertainty/ measured quantity) x 100
Significant figures - + and -
Result has same number of decimal places as the measurement with the fewest number of decimal places
Significant numbers - x and /
Same number of significant figures as the measurement with the least figures
Molecular Formalue
Chemical formula that refers to discrete molecule
Naming - ionic compounds
Cation followed by anion
Covalent compounds
Carbon first, followed by hydrogen then remaining elements in alphabetical order
Naming - inorganic compounds
Element closest to the left of periodic table appears first
First element retains elemental name, second element has suffix ide
Oxoanions
Root name from central atom
Oxoanion with fewer molecules when 2 different
-ire
Oxoanions with more atoms S uffix when 2 different oxoanions
-ate
Alcohol
Functional group + oxygen + hydrgon
Aldehydes
Functional group+ carbon=oxygen + hydrogen
Ketone
Functional group+ carbon=oxygen + functional group
Carboxylic Acids
Functional group + carbon=oxygen+ OH
First she’ll
2 electrons
Second she’ll
Up to 8 electrons
Third she’ll
Up to 18 electrons
Forth and other shells
Up to 32 electrons
Covalent bond - energy
Very strong bonding so it takes a lot of energy to break
Ionic attraction
Attraction of opposite charges
Hydrogen bonds
Attraction between h+ and strongly electronegative atom
Hydrophobic interactions
Interactions of non polar substances in the presence of polar substances
Van der waals interactions
Interaction of electrons of non polar substances
Sharing of electrons covalent bonds
If 2 of same atom then sharing is equal
If 2 different atoms then sharing isn’t equal and the one with the greater force will hold electrons closer
