UNIT 1 - test 1 (ch2 and 5) Flashcards
(27 cards)
List particles in atoms, their mass and charges
protons - positive m-1
neutrons - neutral m-1
electrons - negative m- 1/1800
MASS NUMBER
the total number of protons and neutrons in a nucleus.
ATOMIC NUMBER
total number of protons in the nucleus
isotopic symbol
aXe
a - mass number (protons + neutrons_
X - element
e - atomic number (protons)
ISOTOPE
atoms that have the same number of protons (atomic #) but different numbers of neutrons (dif mass numbers)
eg.) carbon 12, 13 and 14
ATOMIC EMISSION SPECTRA
when atoms are heated they can produce coloured light
(if the light is passed through the prism from the flame test, it produces a spectrum with a black background and coloured lines)
VIOLET - high-energy
RED - low energy
FLAME TEST
- cations control flame colour
1. electrons start at the ground state
2. when heated jump to an excited state to different valence electron
3. jumps back to ground state (light energy produced)
State the limitations of the shell model.
- cannot accurately predict the emission spectra of atoms with more than 1 electron
- unable to explain why electron shells can hold 2n2 electrons
- doesn’t explain why 4th shell accepts 2 electrons before 3rd shell is completely filled
Explain the quantum model (subshell) of the atom
- subshells exists within shells (s,p,d,f)
- made up of orbitals
- 1 subshell - 1s
- 2 subshell - 2s2p
- 3 subshell - 3s3p3d
Describe the difference between shells, subshells and orbitals.
shells - surround the nucleus where electrons sit (1,2,3 etc)
subshell - exist within subshell (s,p,d,f)
orbitals - a region of space around a nucleus where electrons are found )can hold 2)
State how many electrons are in each shell, subshell, and orbital?
2, 8, 18, 32
groups 1, 2, 17 and 18
1- alkali metals
2 - alkaline earth metals
17 - halogens
18 - noble gas
electronegativity
a measure of how strongly an atom attracts electrons when it forms a bond with another atom
(higher the electronegativity, the stronger the atom pulls electrons toward itself)
IONIC COMPOUNDS
chemical combinations of metallic and non-metalic elements
explain why elements gain or lose electrons (cations + anions definitions)
- to have a full outer shell
- metal atoms LOSE electrons becoming + charge metal ions (CATIONS)
- nonmental atoms GAIN electrons becoming - charged ions (ANIONS)
example of cation + anion
cation - calcium, lead, aluminium, lithium
anion - chloride, hydroxide
OCTET RULE
- atoms gain or lose electrons to obtain a stable electronic configuration identical to the noble gas closest to them on the periodic table.
Describe the structure of sodium chloride?
continuous lattice structure
- each sodium ion surrounded by 6 chloride ions
- each chloride ion is surrounded by 6 sodium ions
List the properties of ionic compounds
- high melting point
- hard, but brittle
- electrical conductivity
- solubility
HIGH MELTING POINT
- high melting points as ionic bonds between cations + anions r very string
HARD, BUT BRITTLE
- strong force is needed to disrupt ions in ionic compound because electrostatic forces are string
- cant be easily scratched but if smashed by hammer it would break (brittle part)
ELECTICAL CONDUCTIVITY
- must conatin charged partciles tyhat are free to move to conduct eletcircity
- in solid form ions arent free to move bc of lattice structure therefore, they cant conduct electricity
(must melt)
SOLUBILITY
how soluble a compound is in a solvent
1. soluble
- dissolve
- ions break away from ionic lattice + mix w/ water molecules
2. insoluble
- ions remain bonded together in ionic lattice and do not form a solution
polyatomic ion, and examples
ions which consist of more than one atom
- nitrate ion, NO3-, contains one nitrogen atom and three oxygen atoms
