1. Inside the Atom

2. Let’s Investigate the Atom

3. Atoms are composed of three type of particles: SUBATOMIC PARTICLES: protons, neutrons, and electron.
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 grams).

4. What makes up the atom. Protons and neutrons reside in the nucleus
What makes up the atom? Protons and neutrons reside in the nucleus. Protons have a positive (+) charge, neutrons have no charge. They are neutral. Electrons are in orbitals, or electron clouds, around the nucleus. They have a negative charge (-).

6. Atomic Number
The number of _________ in the nucleus of an atom determines an element's atomic number.
The number of protons in the nucleus of an atom determines an element's atomic number.

7. So what is the Atomic Number?

8. C 6 Atomic number. Atomic symbol Carbon 12.011 Element name
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
Atomic #
6 neutrons

9. The number of electrons, protons, and neutrons can be changed in an atom and changes the atom!

10. I. Changing Electrons
An atom that changes the number of electrons is called an __________.
The number of ________ and ________ stays the same. No change in atomic number or ____________ ______________.
An atom that changes the number of electrons is called an ion.
The number of protons and neutrons stays the same. No change in atomic number or mass number.

11. II. What is make an ion?
If the atom loses electrons, the atom becomes ____________ charged.
If an atom gains electrons, the atom becomes ____________ charged.
If the atom loses electrons, the atom becomes positively charged.
If an atom gains electrons, the atom becomes negatively charged.

12. Positive ion______________
(4 +) + (3-) = 1+

13. Negative ion______________
(4 +) + (5-) = 1-

14. III. Changing Neutrons
Changing the number of neutrons in an atom makes an ________________.
Have the same _______ _____________
Have different mass numbers (number of __________ + ___________)
Changing the number of neutrons in an atom makes an isotope.
Have the same atomic number(number of protons))
Have different atomic mass numbers (number of protons + neutrons

15. IV. Changing Protons
Changing the number of protons causes ________________- changing from one element to another.
The _________________and __________________ changes
Changing the number of protons causes transmutation changing from one element to another.
The atomic number and mass number changes

16. Sample Problem 1: For an atom with 15 protons, 16 neutrons, and 18 electrons…
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?

17. Sample Problem 2: For an atom with 28 protons, 31 neutrons, and 26 electrons…
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?

18. Vocabulary 79. Democritus 80. John Dalton 81. Atomic theory
82. J.J. Thomason
83. Ernest Rutherford
84. Niels Bohr
85.James Chadwick
Electron clouds
Nucleus
Protons
Neutrons
Electrons
Atomic mass
Atomic number
Ion
Isotope
Transmutation