1. The Atom

2. AMU = atomic mass unit Part Where Mass Charge proton electron
Clouds (energy levels) outside the nucleus
1/1800 th AMU
neutron
no charge
AMU = atomic mass unit

3. ~1800 electrons
1 proton

4. Parts of the Atom

5. Box on the Periodic Table

6. Energy Levels 1st energy level must fill with 2 3rd energy
level is not
filled
2nd energy level
Is full with 8

7. Isotopes of Hydrogen
H-1
H-2
H-3

8. Warm- Up: Isotopes of Magnesium
Magnesium has three isotopes, Mg−24, Mg−25, and Mg−26. The percentage of each in order is 78.70%, 10.13%, 11.17%. Calculate the relative atomic mass of Magnesium.
24 x = 18.88
25 x =
26 x =
18.88
2.532
24.32

9. Bohr Diagrams
Find the element on the Periodic Table
Put the name above and the symbol below the space for your diagram
Find the #of protons
Round the atomic mass to closest whole # and subtract the # of protons for # of neutrons
Draw the electrons in their shells.

10. Warm-up #1
What is the common name of the element illustrated to the right?
What is the symbol of this element?
What is the atomic number of this element?
The atomic number tells us how many _____are in this atom.
What is the atomic mass of this element?
The atomic mass tells us how many ____are in this atom.
How many electrons are in this atom?
Draw a Bohr Diagram of this atom (the high school way)

11. Warm up: Bohr Diagram
In your notebook, draw the following atom the high school way:
Argon

12. The HIGHSCHOOL Way
Argon
18P
22N 8 8 2 Kr

13. Warm Up: What are three ways that an atom can be drawn to show the same information?

14. ISOTOPES
To write the name of an isotope, we write the name of an element followed by its mass number, eg. Carbon-14 (which contains 6 protons and 8 neutrons in each atom).
Did you know?
Some isotopes are radioactive, meaning they give off radiation through a nuclear change, while others are known as stable, meaning they do not give off any radiation,
Any atom that has an atomic number of 83 or higher is also radioactive, regardless of what isotope it is.
Radioactive atoms and isotopes are dangerous to anything living thing except in the smallest possible amounts

15. Calculate the atomic mass of Carbon

16. Carbon
There are three naturally occurring isotopes of carbon on Earth:
99% of the carbon is carbon-12
1% is carbon-13
carbon-14 occurs in trace amounts, e.g.
making up as much as 1 part per trillion
( %) of the carbon in the
atmosphere.
The half-life of carbon-14 is 5,730±40 years. It
decays into nitrogen-14 through beta decay.

18. Otzi- found in a receding glacier
3300 BC determined by carbon dating
Oldest natural human mummy
Found in 1991 in Italian Alps where a glacier had receded
Ötzi was a high-altitude shepherd
Last meal was deer meat; hair samples gave clues about his diet

19. Otzi the Iceman

20. Which of the following are isotopes of each other?
(a) An atom with 17 protons and 18 neutrons?
(b) An atom with atomic number 16 and atomic mass 32?
(c) An atom with atomic number 16 and 18 neutrons?
(d) An atom with 16 protons and 18 neutrons?
(e) An atom with 17 protons and 20 neutrons?
(f) An atom with atomic number 16 and atomic mass 33?
(g) An atom with 15 protons and 16 neutrons?
Answer key: a & e; b, c, & f; g

21. Shaping Up Reflection
Heart - One thing I love about this topic…
Square- Four strategies that would have really worked in learning this material…
Triangle- Three things that I’ve learned…
Circle- One thing that is going around in your head…

22. The period # (row)on the Periodic Table of Elements tells you how many energy levels a atom has.

24. Valence Electrons Electrons in the outer shell
Determines which elements will react
with each other
Chemistry happens here
Full when it has 8 electrons
(2 in the case of hydrogen and helium)
An atom will either lose all of its valence electrons or gain to equal 8 during chem. reactions (becomes happy)
Metals usually lose electrons—Why?
Nonmetals usually gain electrons

25. Summary of Periodic Table Trends
Moving Left --> Right
Atomic Radius Decreases
Ionization Energy Increases
Electronegativity Increases
Moving Top --> Bottom
Atomic Radius Increases
Ionization Energy Decreases
Electronegativity Decreases

28. Half-life
The half-life describes the amount of time needed for half of a sample of unstable atoms or particles to undergo decay. Thallium-208, for example, decays into lead-208 with a half-life of 3.05 minutes. This means that half of a sample of thallium-208 will decay into lead-208 over the course of 3.05 minutes.
Scientists cannot predict when a particular atom or particle will decay. They only know that, on average, half of a sample will decay during the span of one half-life.
3.08 min
3.08 min