Chapter 4- Structure of an Atom
neutron
0 charged sub-atomic particle located in the nucleus and responsible for other half of mass. relative mass is 1 amu
atomic mass unit (amu)
1/12th the mass of a carbon-12 atom.
Dalton's atomic theory
All matter is made of atoms. Atoms are indivisible and indestructible. 2) All atoms of a given element are identical in mass and properties 3) Compounds are formed by a combination of two or more different kinds of atoms. 4) A chemical reaction is a rearrangement of atoms.
isotopes
Atoms with the same number of protons but different numbers of neutrons
Aristotle
Believed that matter was made up of earth, air, fire, and water. Didn't believe in empty spaces. Views lasted 2000
Ernest Rutherford
Discovered protons and empty space of atom using alpha particles. Help create atomic model with proton containing nucleus and empty space. Also, majority of atom's mass is in the nucleus
quantum number
Each orbit, around the nucleus, was given a number for energy levels
Gold Foil Experiment
Experiment in which alpha particles were beamed towards gold foil conducted by Ernest Rutherford
Plum Pudding model
JJ. Thomson's chocolate chip cookie model of the atom after discovering electron. Electrons are chips. dough is positive.
ground state
The lowest allowable energy state of an atom
Robert Millikan
Use oil drop apparatus to determine charge of electron and mass
cathode ray
an electric charge is applied, a ray of radiation travels from the cathode to the anode
Bohr's Model of the atom
an electron moves around the nucleus only in certain allowed circular orbits.
JJ. Thomson
discovered electron using cathode ray tube experiment
James Chadwick
discovered the neutron and the atom's additional mass in the nucleus.
atomic mass
element is the weighted average mass of the isotopes of that element.
Democritus
first person to propose the idea that matter was not infinitely divisible, but made up of individual particles called atomos. Believed in empty space around atoms, atoms indivisible, indestructible, and different kinds with different properties and shapes
orbital shells
location of where electrons can be placed
atomic number
number of protons in the nucleus of an atom identifies the element
Sub-atomic particle
part of the building blocks of atoms, electrons, protons and neutrons
electrons
particles carrying a negative charge of 1- and have mass of 9.1x10^-28 g or 1/1840 of Hydrogen , occupy space around nucleus
proton
positively charged sub-atomic particle located in the nucleus with 1+ charge, relative mass is 1 amu
nucleus
proton and neutron containing center of an atom
atom
smallest particle of an element that retains the properties of the element
quantum
the minimum amount of energy that can be gained or lost by an atom.
mass number
the sum of the protons and neutrons in the nucleus