DALTON
• all matter is composed of tiny indivisible particles called atoms; • atoms cannot be created or destroyed;• atoms of the same element are alike in every way;• atoms of different elements are different;• atoms can combine together in small numbers to form molecules.Using this model we can understand how elements react together to make new substances called compounds.
THOMSON
Atoms are plum pudding, negative charged electrons in a positively charged substance
RUTHERFORD
Nucleus positively charged.
BOHR
Orbit or energy level around positively charged.
Atomic Number Z
The number of protons in the atomThe atomic number is also equal to the number of electrons
Mass Number A
Depends on the number of protons and neutronsA = p + n
Em cima: MASS numberEmbaixo: ATOMIC number
True
Isotopes
Atoms of same element with different number of neutrons
Cation
Positive ionWhen an atom loses electrons
Anion
Negative ionWhen an atom gain electons
Quando eu tenho um cátion Al 3+:
O número de protons continua o Z.Só altero o numero de elétrons.
Mass spectrum
Tenho 100 atoms60 atoms -> mass: 6940 atoms -> mass: 71(60 x 69) + (40 x 71) = 69806980/100 - 69,80
Sodium
orange flame
potassium
blue flame
copper
green flame
Different colours of visible light have different wavelengths; red light, for example, has a longer wavelength than blue light.
TRUE
V = LAMBIDA X FREQUENCY
TRUE
White light is a mixture of light waves of differing wavelengths or colours. We see this when sunlight passes through a prism to produce a continuous spectrum or as a rainbow when light is scattered through water droplets in the air.
TRUE
As well as visible light, atoms emit infrared radiation, which has a longer wavelength than red light, and ultraviolet radiation, with a shorter wavelength than violet light.
TRUE
At the short wavelength end (on the left) of the spectrum are γ rays, X rays, and ultraviolet light.
TRUE
At the longer wavelength end of the spectrum (on the right) are infrared radiation, microwaves, and radio waves.
TRUE
The excited state produced is, however, unstable and the electron soon falls back to the lowest level or ground state.
TRUE
The energy the electron gives out when it falls into lower levels is in the form of electromagnetic radiation.
TRUE
IONIZATION ENERGY
THE ENERGY NEEDED TO REMOVE AN ELECTRON FROM THE GROUND STATE OF AN ATOM IN A MOLE OF GASEOUS ATOM, IONS OR MOLECULES
According to Heisenberg's Uncertainty Principle we cannot know where an electron is at any given moment in time.
TRUE
ERWIN SCHRODINGER
A WAVE EQUATION COULD BE USED TO DESCRIBE THE BEHAVIOUR OF AN ELECTRON IN THE SAME WAY THAT A WAVE EQUATION COULD BE USED TO DESCRIBE THE BEHAVIOUR OF LIGHT
ionization energy increases from left to right across a period, as the nuclear charge increases
true
As the electrons are removed from the same main energy level, there is an increase in the force of electrostatic attraction between the nucleus and outer electrons.
true
Ionization energy decreases down a group as a new energy level, which is further from the nucleus, is occupied.
Less energy is required to remove outer electrons that are further from the attractive pull of the nucleus.