Scientists
The number of protons in an atom of an element is its
What is : atomic number
Neutron is _______ charged
What is : uncharged/ neutral
A (n) _____ is a very small particle that is the basic unit of matter.
Atom
What two particles make up the net charge of an atom nucleus?
What is : protons and electrons
What particle lives in the rings in the Bohr diagram?
Electrons
What structure did Rutherford discover was in an atom after his gold foil experiment?
What is : A nucleus
The positively charged particle
What is : A proton
Which group of metals are the most reatctive?
Alkali metals
Two or more atoms make up structure called a...
Molecule
________ is the weighted average mass of all of an element's isotopes.
Average atomic mass
Atoms with more neutrons have more mass than do atoms with fewer neutrons.
True or False
What particle did J.J. Thomson discover?
What is : electron
Isotopes of the same element have the same number of protons but different number of _________
What is : neutrons
The current atomic theory includes the ________ model of electrons.
What is : electron cloud
Which subatomic particle determines the "identity" of the atom?
atomic number/number of protons
What do excited electrons emit when they fall back to their ground state?
What is energy/light?
Draw a Bohr model of Helium
2 electrons in the first shell only
The plums in Thomson's plum-pudding model of the atom represent:
What is :electrons
In an atom, which has the least mass? A: nucleus B: proton C: neutron D: electron
What is : electron
What are elements with similar chemical properties called?
What is : groups/family
How many "shells" or "rings" does an oxygen atom have- based on the Bohr model?
2 shells
How many electrons does an oxygen atom have?
8 electrons
How many electrons can fit in the first, second, and third shell?
2,8,8
What did Bohr, Democritus, Thomson, Dalton, and Rutherford all have in common? A: They each identified the electromagnetic force of atoms B: They each identified new electron clouds C: They each developed ideas about atoms D: They each conducted experiments with ions
What is : C: They each developed ideas about atoms
Describe the difference between atomic number and mass number *Multiple sentence answer*
What is : The atomic number is the number of proton in an atom. The Mass number is the sum of the number of protons and neutrons in an atom of a particular isotope
The most dense structure in an atom called _______ is made up of ______ and ______.
What is : nucleus, protons, and neutrons
Which two subatomic particles determine the atomic mass?
Protons and Neutrons. Electrons are too light (relatively) to count towards the atomic mass.
Which determines the identity of an element?
A) its mass number
B) the charge of the atom
C) the number of its neutrons
D) the number of its protons
Which modern scientist proposed the atomic theory that supported some of Democritus' ideas?
Dalton