Atomic Theory Flashcards
(27 cards)
What is the basic unit of matter?
Atom
True or False: Atoms can be created or destroyed in a chemical reaction.
False
Who proposed the first atomic theory in the early 1800s?
John Dalton
Fill in the blank: An atom consists of a nucleus surrounded by ______.
electrons
What are the three main subatomic particles?
Protons, neutrons, and electrons
What is the charge of a proton?
Positive
What is the charge of an electron?
Negative
What is the mass of a neutron compared to a proton?
Approximately equal
True or False: Electrons are located in the nucleus of an atom.
False
What is the atomic number of an element?
The number of protons in the nucleus of an atom
What determines the chemical properties of an element?
The arrangement of electrons
Fill in the blank: Isotopes of an element have the same number of protons but different numbers of ______.
neutrons
What is the concept of atomic mass?
The weighted average mass of an element’s isotopes
Who discovered the electron?
J.J. Thomson
What model of the atom did Rutherford propose?
The nuclear model
True or False: The modern atomic model is based on quantum mechanics.
True
What is the principal quantum number?
A number that indicates the energy level of an electron
Fill in the blank: The uncertainty principle was formulated by ______.
Werner Heisenberg
What is a valence electron?
An electron in the outermost shell of an atom
What is the role of neutrons in the nucleus?
To provide stability
What does the term ‘ion’ refer to?
An atom or molecule with a net electric charge due to the loss or gain of electrons
What is a cation?
A positively charged ion
What is an anion?
A negatively charged ion
Fill in the blank: The periodic table is arranged by increasing atomic ______.
number
