1. Atoms and their Isotopes
POGIL Activity Review

2. Atoms Entire world is composed of atoms Atoms are composed of
Proton (charge +1) weigh 2000x more
Neutron (no charge) than electrons
Electron (charge -1)
Properties of an atom are determined by the number of P+, N0, and E-

3. Key Questions
1. The atomic number [Z] tells the reader the number of protons and electrons in a neutral atom.
2. The mass number [A] tells the reader the number of protons and neutrons.

6. 3. The number of protons is equal to the number of electrons.
4. The electrical charge of an atom with an equal number of protons and electrons is neutral or no charge.
5. The protons and neutrons are located in the nucleus of an atom.
6. The two sodium isotopes have the same number of protons and electrons.
7. The two sodium isotopes have different number of neutrons.

7. Isotopes of an element A Mass Number (number of protons and neutrons)
Atom has the same number of protons but a different number of neutrons
Neutral atoms have equal number of protons
and
electrons
Atomic Symbol Notation
A Mass Number (number of protons and neutrons)
X Atomic Symbol
Z Atomic Number (number of protons)

8. Isotope Example

9. 8. The following can distinguish an atom of one element from an atom of another element:
Mass  the number of protons and electrons
Atomic number  the number of neutrons

10. Exercises 1. Similarities include: 2. Differences include:
They are the same element
They each have 17 protons
They each have 17 electrons
2. Differences include:
They have different mass numbers.
Cl-35 has 18 neutrons
Cl-37 has 20 neutrons.

11. 3. Atomic symbols for the two isotopes of carbon:

13. Name
Symbol
Atomic Number (Z)
Mass Number (A)
Number of Neutrons
Number of Electrons
Oxygen 16 8
Nitrogen 14 7
Sulfur 34 18
Hydrogen 1 3 2
Magnesium 24 12 25 13
Uranium
238 92
146
Krypton 84 36 48 O N S H H Mg Mg U Kr

14. 1 fm = 1 x m
1 pm = 1 x m
Problems
1. The radius of a Cl nucleus is 4.0 fm, and the radius of a Cl atom is 100 pm. How many times larger is the diameter of the Cl atom than the diameter of a Cl nucleus?
2. Two objects that have the same ratio of length.

15. Problems
Volume = 4/3(pi)*r3
3. How many times larger is the volume of the atom than the volume of the nucleus?

16. 4. Use a periodic table to fill in the missing information in the following table.
Name
Symbol
Atomic Number Z
Mass Number A
Number of Neutrons
Number of Electrons
Oxygen 16 O 8 7 34 S 18