atoms and electrons

atomic orbital

a region of space with a high likelyhood of finding an electron

atomic number

the number of protons in the nucleous of an atom

how did jj thomson account for the fact that atoms are electrically neutral ?

the plum pudding model

evidence for the existence of energy levels ?

the atomic absorption spectrum

state the limitations of bohrs atomic theory?(4)

only works for hydrogen , wave nature of electrons not included, heisenbergs uncertainty principle not included , did not account for sublevels

what are isotopes?

atoms with the same atomic number but a different mass number

relative atomic mass

the average mass of an atom of a element relative to 1/12th of the carbon-12 isotope

what are the fundamental processes of mass spectrometry

vapourization , ionisation , acceleration , seperation , deflection

state daltons atomic theory

atoms are small and indivisible , all mater consists of atoms , atoms of the same element are identical

name the scientist whos work on cathode rays led him to him identifying the electron as a subatomic particle

thomson

what happens in a radioactive nucleus during beta decay

neutron changes into a proton and an electron is emitted

what is an electrons ?

a subatomic particle that orbits the nucleus and is located in an electron cloud

why might an electron not occupy the n=1 energy level

too much energy

name the series of visible lines on the hydrogen emission spectrum

balmer

why are group 18 elements chemically inert

have a stable , full outer shell

why are group 2 elements highly reactive

do not have a stable full outershell

cathode rays

beams of negatively charged particles called electrons

what was the purpose of milikans oil drop experiment ?

to measure the charge on an electron

why do electrons not stay in E1,E2 or any of the above energy levels ?

higher energy states are unstable

the energy level in which visible rays of light are seen

N=2

how does modern atomic theory describe the behavious of electrons

electrons exhibit both wave and particle properties

give one way of detecting the presence of cathode rays in a vacuum tube ?

paddle wheel pushed , shadow cast by anode

boyles understanding of an element

an element cannot be split into anything simpler

use bohrs atomic theory to account for the emission spectrum of a hydrogen atom

electrons occupy fixed energy levels , in the ground state electrons occupy the lowest possible energy level , electrons can move from to a higher energy level is a certain amount of energy is received , energy absorbed must equal energy difference between ground state and excited state , excited state is unstable , electrons fall back down , energy emitted as a photon of light

heisenbergs uncertainty principle

not possible to measure the exact location and momentum of an electron in an atom simultaneously

properties of cathode rays

streams of negatively charged particles , travel in straight lines , enough force to move a small paddle wheel

energy level

the fixed amount of energy of an electron in an atom

aufbau principle

electrons must occupy lowest energy level before occupying higher energy levels

process of the atomic absorption spectrum

white light passed through a gaseous sample of an element , when light is detected and observed there are lines/gaps in the spectrum , electrons in the atoms of gas have absorbed the light at specific wave lengths, wave lengths missing are the same ones that would be present in the emission spectrum