Subatomic Particles
Main 2 forces between particles within the nucleus
What are electrostatic forces and strong nuclear forces?
atoms of the same element but different mass
What are isotopes
Who developed the theory that electrons are in orbitals or distinct energy levels outside the nucleus?
Who is Bohr?
Name 2 ways isotopes are distinct from each other
They have different #'s of neutrons; their masses are different
This Greek philosopher declared that all matter was made of tiny indivisible particles called atoms
Who is Democritus?
In describing an isotope's mass number, atomic number and numbers of protons, electrons, and neutrons - which 3 have the same value?
What is the atomic number, number of electrons, number of protons.
This scientist responsible for discovering the charge on an electron. How?
Who is Robert Milikan? oil drop experiment
This part of the periodic table can be used to determine the number of protons in an atom.
What is the atomic number?
The Law that states that a chemical compound always contains the same elements in the exact same proportions by mass?
What is the law of definite proportions?
a neutrally charged particle
What is the neutron?
These particles determine the identity of the atom
What is the proton?
What is term for the number "35.45" for chlorine (on the periodic table)? How is it determined?
What is its average atomic mass. Determined by the weighted average of each naturally occurring isotope of chlorine.
What is Avogadro's number?
A mole, equal to 6.022 x 1023
These particles are ;largely responsible for the chemical properties of an atom.
What are the electrons?
Three discoveries by Rutherford, and the name of his experiment.
Gold foil experiment --> protons; dense nucleus; that atom is mostly empty space.
What is the isotope name for an element with 20 protons and 22 neutrons?
What is Calcium - 42?
How can you know the molar mass of an element?
It is numerically equivalent to the element's average atomic mass in atomic mass units (a.m.u.'s) - found on the periodic table.
Atoms combine in _______________, which is a statement of the Law of _______________.
small whole-number ratios;
[law] of multiple proportions
Discoverer of electrons, and the name of his model.
Who is JJ Thomson; plum-pudding.
What is the mass number and atomic number for an atom with 34 protons and 44 neutrons?
A = 78; Z = 34
3 of the 5 postulates of Dalton's atomic theory. Which one(s) are no longer considered valid?
1)All elements are composed of small particles [atoms]
2)All atoms of the same element have the same mass; atoms of different elements have different masses [CHANGED]
3)Atoms only combine in small, whole number ratios
4)In chemical reactions, atoms are combined, separated or rearranged.
5)(implied) Atoms cannot be subdivided, created or destroyed. [CHANGED]