Atoms
All matter is made of atoms. What is the name of two of more atoms of different elements chemically joined?
Compound
The charge of an electron is?
Negative
What are the rows of called?
Periods
Who was the first to claim that all matter was made of small particles?
Democritus
What atomic model includes a nucleus and electrons across multiple shells or “ladder steps”?
Bohr’s Atomic Model
What does the Atomic number indicate?
Number of protons in the nucleus.
The charge of a proton is?
Positive
What are the columns called?
Groups
Who initiated atomic theory through experiments on combining gases?
Dalton
What differs across isotopes of an element?
number of neutrons
What does the Atomic Mass number indicate?
Sum of the protons and neutrons in the nucleus.
The charge of a neutron is?
Neutral
What do the elements in a Group have in common?
The number of valence electrons
Who discovered the electron?
Thompson
Going from top to bottom of Group 1A, what does the reactivity of alkali metals do?
Increases
Who was the first scientist to see an atom?
No one has seen an atom
How does the energy state of an electron change as it moves closer to the nucleus?
It decreases
What does the number of valence electrons in the outermost shell determine?
Similar properties, like reactivity
Who discovered the proton?
Rutherford
Going from top to bottom of Group 8A, what does the reactivity of the noble gases do?
It doesn’t change
What law says that matter cannot be created or destroyed?
Conservation of matter / mass
What does an electron have to do to move closer to the nucleus?
Release energy
The Atomic number of Silicon-28 is 14. How many electrons, neutrons and protons are there?
14 electrons, 14 protons, 14 neutrons
Who theorized that electrons existed in shells of different energy levels?
Bohr
What is another name for the electron cloud model?
Quantum mechanical model