Atomic Structure
Particle in an atom with a positive charge
Proton
Total number of named elements on the periodic table
118
Material made of identical atoms
Element
Na
Sodium
An atom has 15 protons and 16 neutrons in its nucleus. How many electrons does it have
15
Pathways where electrons can be found
Energy levels
Most elements on the periodic table are
Metals
Letters that stand for each element
Atomic symbol
Potassium
K
An atom has an atomic number of 30 and an atomic mass of 70. How many neutrons does is have
40
The area that contains the mass of an atom
Nucleus
A vertical column on the periodic table
Total number of protons and neutrons in an atom
Atomic mass
Pb
Lead
The electrons in the outer energy level
Valence electrons
Particle in an atom with a negative charge
Electron
Group 1 on the periodic table
Alkali metals
Atomic number equals number of
Protons
Iron
Fe
An element in period 3 and group 5 has how many valence electrons
5
Unit used to measure the mass of 1 proton or 1 neutron
AMU
Periods on the periodic table tell us the number of
Energy levels
Elements that share properties with metals and nonmetals are called
Metalloids
Au
Gold
Fluorine's atomic number is 9 and it has 10 neutrons and 9 electrons. What is its atomic mass
19