Unit 2 Chemistry: Atomic Structure Flashcards
What are the three subatomic particles that an atom is made up of?
Protons, neutrons, and electrons
What is the charge of a proton?
Positive
What is the charge of a neutron?
Neutral
What is the charge of an electron?
Negative
What is the nucleus?
The center of an atom
What is held in the nucleus of an atom?
Protons and neutrons
What is outside the nucleus, in the energy levels?
Electrons
Who was the first person to think about an atom’s existence?
Democritus
What did Democritus believe atoms were composed of?
Tiny indivisible particles
What did Dalton come up with?
He came up with 4 major points (postulates) to his theory about the atom.
Point 1 of Dalton’s theory:
All elements are composed of indivisible particles called atoms.
Point 2 of Dalton’s theory:
Atoms of the same element are identical. The atoms of any one element are different from those of another.
Point 3 of Dalton’s theory:
Atoms of different elements mix or combine in whole-number ratios.
Point 4 of Dalton’s theory:
Chemical reactions occur when atoms separate, join, or rearrange. In a chemical reaction, atoms of one element never change into another.
Who discovered the electron?
J.J. Thomson
What experiment did Thomson use to figure out that opposites attract?
Cathode Ray Tube Experiment
What experiment did Thomson use to discover the electron?
Plum Pudding model
Who discovered the Nucleus?
Ernest Rutherford
What experiment did Rutherford use to discover the nucleus?
Gold Foil experiment
What did most of the alpha particles conclude?
The atom is mostly empty space.
Who discovered the proton?
Eugene Goldstein
Who discovered the neutron?
James Chadwick
What is the charge of a proton?
1
What is the charge of a neutron?
0
What is the charge of an electron?
1
What is the mass of a proton
1
What is the mass of a neutron?
1
What is the mass of an electron?
1/1840
When is an atom considered neutral?
When it has the same number of protons and electrons.
What is the atomic number?
It is the number of protons in an element.
What is the atomic mass?
It is the weighted average of all the element’s isotopes.
What is the mass number?
It is the number of protons and neutrons combined.
What are isotopes?
They are atoms with the same number of protons but a different number of neutrons.
What is an ion?
They are an atom or groups of atoms that has a positive/negative charge.
What is a cation?
It is an atom of groups of atoms with a positive charge.
What is an anion?
It is an atom or groups of atoms with a negative charge.
What group of elements tends to lose electrons?
Metals
What group of elements tends to gain electrons?
Nonmetals
What charge is gained when electrons are lost?
Positive
What charge is gained with electrons are gained?
Negative
