Parts of an atom
Center, or core, of an atom
nucleus
The number of protons found in the nucleus of an atom is called ___________
atomic number
The total mass of the protons and neutrons in an atom is called ________
atomic mass
Elements are arranged on the periodic table according to their
atomic number
List the subatomic particles in an atom
proton, neutron and electron
Which element has the smallest amount of protons?
Hydrogen
What unit did scientists develop to measure the mass of an atom?
atomic mass unit or amu
The horizontal rows are called ___________ and vertical columns are called _______________.
groups and periods
Which subatomic particle has a positive charge and is located in the nucleus?
proton
How many protons does an atom of oxygen have?
8
How do you find the mass number of an atom?
by rounding the atomic mass number to the nearest whole number
Elements in the same group have similar
physical and chemical properties
Which subatomic particle has a negative charge and is located in the nucleus?
neutron
If you know the number of protons in an atom you also know the number of __________.
electrons
What is the mass number of oxygen?
16
The first letter of a chemical symbol is always written as a
capital letter
Which subatomic particle has a neutral charge and is located outside the nucleus?
electron
No 2 elements have the same number of ________
protons
Lithium has a mass number of 7 and an atomic number of 3. How many neutron are there in an atom of lithium?
4
How many element are in the chemical formula for salt NaCl?
2