Atoms and their Isotopes POGIL Activity Review Atoms

Atoms and their Isotopes POGIL Activity Review

Atoms � Entire world is composed of atoms � Atoms are composed of › Proton (charge +1) › Neutron (no charge) › Electron (charge -1) � Properties weigh 2000 x more than electrons of an atom are determined by the number of P+, N 0, and E-

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.

� 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.

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

Isotope Example

� 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

Exercises � 1. Similarities 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.

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

Name Symbol Atomic Number (Z) Mass Number of Number (A) Neutrons Number of Electrons Oxygen 16 8 8 7 14 7 7 34 16 S 1 1 H 3 1 H 16 34 18 16 1 1 1 0 1 3 2 1 24 12 12 12 25 13 12 92 238 146 92 36 84 48 36 Nitrogen Sulfur Hydrogen Magnesium Uranium Krypton 14 7 25 12 O N Mg Mg 238 92 U 84 36 Kr

Problems 1 fm = 1 x 10 -15 m 1 pm = 1 x 10 -12 m � 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.

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

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