Launch:10/1   Grab a your binder and immediately take a seat

  Write a complete sentence about why it is correct!

5.  The most abundant isotope of lead contains 82 protons and 124 neutrons packed closely together in the nucleus. Why do protons stay together in the nucleus rather than fly apart?

a.  Electrons in neighboring atoms neutralize repulsive forces between protons.

b.  Neutrons effectively block the protons and keep them far apart to prevent repulsion.

c.  Electrostatic forces between neutrons and protons hold the nucleus together.

d.  Nuclear forces overcome repulsive forces between protons in the nucleus.

Unit #3: Nuclear Processes

What are isotopes? Mr. Heffner 10/1/09

What are isotopes?   Isotopes are…

  atoms of the same element that have different numbers of neutrons.

Drawing Atoms   # protons = atomic number

  # neutrons = atomic mass – atomic number

  # electrons = # of protons

Two ways to express? 1.  Element name, hyphen, atomic mass

Helium – 4 2.  Element symbol, atomic mass, atomic number

He 4 2 Atomic

number

Atomic mass

What is the same?   The number of protons = atomic number

  The number of electrons

What is the different?   The number of neutrons

  The atomic mass

Isotope Activity   Groups of 4

  Do not eat the skittles!

  One person will build the isotope, while the others watch and give feedback

  Then, all students will draw on their own paper

  Finally, students will be asked to express the isotope in an alternative way

Exit Slip 1.  An isotope is a

a.  an atom of an element with the same number of neutrons but different numbers of protons

b.  an atom of an element with the same number of protons but different numbers of neutrons

c.  an atom of an element with the same number of protons but different numbers of electrons

d.  an atom with a very small amount of strong force

2.  The isotope Boron-12 has an atomic mass of a.  5 b.  10 c.  11 d.  12

Exit Slip 3.  The isotope Carbon-14 has

a.  one more electron than Carbon-12. b.  two more protons than Carbon-12.

c.  a lower atomic mass than Carbon-12. d.  two more neutrons than Carbon-12.

4.  Which of the following is an alternative way to express Nitrogen-13?

a.  137N

b.  136N

c.  147N

d.  146N

Exit Slip 5.  Boron-13 has

a.  13 protons, 8 neutrons, and 5 electrons b.  5 protons, 13 neutrons, and 5 electrons

c.  5 protons, 8 neutrons, and 7 electrons d.  5 protons, 8 neutrons, and 5 electrons

Homework   Finish practice questions