the atom lesson 2 chemistry Flashcards
atomic number
number of protons unique to each element on the period table
isotopes
atoms of the same type of element but with different numbers of neutrons
mass number
the sum of protons and neutrons in a particular isotopes of an element
atomic mass
the average mass of the atoms of that element
element
ways of writing a particular isotope
key formulas
number of protons = atomic number, mass number = protons and neutrons
number of electrons
same number of protons
where is all the mass of the atom?
nucleus
what is a protons charge?
positive
what is a neutrons charge
neutral
what is an electrons charge
negative
what is an excited atom?
electrons move to a higher energy level
what is released when an atom loses energy?
light
what subatomic particles change the identity of the atom
proton
what subatomic particle will change the overall charge of an atom
electron
what does the slider do?
changes the speed of electrons
what is the motion of the electrons around the nucleus of an atom?
randomly appears but stays around
what did Democtritus discover?
everything is made up of small particles
what did Aristotle discover?
matter was fundamentally constructed out of atoms
what did Dalton discover?
common substances always broke down into the same element
what did JJ Thomson discover?
the electron
what did Rutherford discover
some particles go through and some bounce back
what did Bohr discover?
electrons orbit the nucleus at fixed energies and distances
what did Heisenberg discover?
it is impossible to determine the exact position and speed of electrons
why is the number called a “mass” number?
because it is the average mass of multiple of an element
which corner of the isotope symbol contains the mass number
top left
where is the atomic number located in the isotope symbol?
bottom left
what are the wavelengths?
radio waves, microwaves, infrared, ultraviolet, x-rays, gamma rays
what is the longest wavelength?
radio
what is the shortest wavelength
gamma rays
what wavelength has the highest energy?
gamma rays
what wavelength has the lowest energy
radio waves
what wavelength has the highest frequency?
violet
what happens when the inside of an atom is heated?
makes the atoms and molecules move faster
what are valance electrons
in the outermost energy
what are core electrons
everything below
