Atoms
Nucleus of the atom
composed of two subatomic particles: protons and neutrons
An element is
a pure substance made of only one kind of atom.
Elements in the same group (column) of the periodic table have
similar chemical properties.
It is divided into
metals, nonmetals and metalloids
Proton
It's a subatomic particle charged positvely
The periodic table is arranged in order of increasing
atomic mass.
Group 1
are known as alkali metals
are found in energy levels (shells) around the nucleus.
negative chage called electron
The atomic number of an element is equal to
the number of protons in its atoms.
Group 2
transition metals
The mass number
is the total of protons and neutrons in the nucleus
The mass number of an atom is
the sum of its protons and electrons.
All elements in the same period have
the same number of valence electrons.
Atoms can join with other atoms to
form stable substances.
each atoms have
protons, neutrons and electrons.
Metalloids have properties of
both metals and nonmetals.