Download Atomic Number

Protons and neutrons are responsible for most of the
atomic mass of an atom, while electrons contribute a
very small amount of mass(9.108 X 10-28 grams).
The number of _________ in the nucleus of an
atom determines an element's atomic number.
Atomic number.
Atomic symbol
6
Element name
C
Carbon
12.011
Average atomic mass *To find the number of protons, see the atomic number.
*To find the number of electrons (see the atomic number, adjust for
charge if there is one)
*To find the number of neutrons, subtract the atomic number from the
atomic mass. Use whole number. Atomic mass -- 12
Atomic #
-6
6 neutrons
 An atom that changes the
number of electrons is called an
__________.
 The number of ________ and
________ stays the same. No
change in atomic number or
____________ ______________.
 If the atom loses electrons, the
atom becomes ____________
charged.
 If an atom gains electrons, the
atom becomes ____________
charged.

(4 +) + (3-) = 1+

(4 +) + (5-) = 1-
 Changing the number of neutrons
in an atom makes an
________________.
 Have the same _______
_____________
 Have different mass numbers
(number of __________ +
___________)
 Changing the number of
protons causes
________________- changing
from one element to another.
 The _________________and
__________________ changes

What is the atom’s net charge?

What is the atomic number of the atom? What is the mass
number?

This is an atom of what element?

What is the atom’s net charge?

What is the atomic number of the atom? What is the mass
number?

This is an atom of what element?
79. Democritus
80. John Dalton
81. Atomic theory
82. J.J. Thomason
83. Ernest Rutherford
84. Niels Bohr
85.James Chadwick
86. Electron clouds
87. Nucleus
88. Protons
89. Neutrons
90. Electrons
91. Atomic mass
92. Atomic number
93. Ion
94. Isotope
95. Transmutation