Definitions
A region of space around the nucleus where electrons are most likely to be found.
What are orbitals?
The first to argue that all matter was made from indivisible particles called atoms.
Who was Democritus?
What is an electron?
Group of elements that are most reactive.
What is Group 1A or alkali metals?
T/F : An electron has the same amount of energy in every orbital.
What is false?
The sum of the protons and neutrons in the nucleus of a cell.
What is the mass number?
His model of the atom describing how electrons move is like planets moving around the sun.
Who is Neils Bohr?
These 2 subatomic particles have almost the same mass.
What are protons and neutrons?
If an atom of gallium has a mass number of 68 and an atomic number of 31, this is the number of neutrons in the nucleus.
What is 37?
T/F: An orbital can contain a maximum of two electrons.
What is true?
The number of protons in an atom.
What is the Atomic Number?
Who is Rutherford?
Have no charge but relatively large mass.
What are neutrons?
The vertical columns of the periodic table.
What are groups/families?
T/F: An atom's lowest energy level only has one orbital.
What is true?
Atoms of an element with the same number of protons but different number of neutrons.
What are isotopes?
Who created the theory that includes 4 postulates stating all elements are composed of atoms, all atoms have the same mass, compounds are made of atoms of more than one element, and chemical reactions occur when atoms join, seperate or rearrange.
Who is John Dalton?
Has far less mass than the other subatomic particles.
What are electrons?
What are the rows of the periodic table called?
What are periods?
T/F: There are more electrons in the orbitals of an atom than there are protons in the nucleus of the atom.
What is true?
Electrons that are in the highest energy level of an atom.
What are valence electrons?
His experiments demonstrated that atoms are the smallest particles of matter, have a negative charge and a positive charge.
Who is J.J. Thomson?
The subatomic particles used in determining the atomic number.
What are protons?
The nuclei of isotopes contain different numbers of ____.
What are neutrons?
This determines an element's chemical properties.
What is the number of valence electrons?