What are periods also known as?
Rows
How many elements are in the periodic table of elements?
118
How do protons affect the mass?
It increases
When was the modern periodic table created?
1869
What are groups also known as?
Columns
What do groups on the periodic table represent?
# of valence electrons
How do neutrons affect the mass?
It increases
Who created the modern periodic table?
Dmitri Mendeleev
What is an atomic number?
The number of protons in the atom's nucleus
What do groups on the periodic table represent?
# of electron shells
How do electrons affect the mass?
Doesn't change
How many protons are in hydrogen?
1
What is an electron shell also known as?
Electron orbital
How many groups are there?
18
Where are neutrons and protons located?
The nucleus
How many electrons are in hydrogen?
1
What are atoms with a different number of neutrons than usual?
Isotopes
What is a compound?
A combination of elements
Where are electrons located?
The electron shell/orbital
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