1. Atomic and Nuclear Theory and the Periodic Table
Review

2. Matter Matter is anything that has mass and takes up space
Matter is made up of atoms

3. Atomic Structure Protons and neutrons are located in the nucleus
Protons have a positive charge
Neutrons have a zero or neutral charge
Protons and neutrons have a mass of 1 atomic mass unit (amu)

4. Atomic Structure cont.
Electrons are found outside the nucleus in the electron cloud
The electron cloud is divided into energy levels (shells)
The outermost energy level is the valence shell which contains the valence electrons
Valence electrons determine the chemical reactivity of the element

5. The atomic number. -tells how many protons are in the nucleus and
The atomic number -tells how many protons are in the nucleus and identifies the element
All atoms of the same element have the same number of protons

6. Isotopes. -atoms that have the same number of protons
Isotopes -atoms that have the same number of protons but different numbers of neutrons
Example
Carbon-12, Carbon-13, Carbon-14
All three atoms have 6 protons
The atoms have 6, 7 or 8 neutrons respectively
“12”,”13”, and “14” represents the mass number of each atom

7. Atomic Mass
The [weighted] average mass of all the different isotopes that make up the element in the proportions found in nature (relative abundance)

8. Periodic Table
Dmitri Mendeleev discovered that certain elements had similar properties – when arranged according to reactivity, there was a pattern
The table is in order of atomic number

9. Periodic Table cont.

10. Periodic Table cont.
Elements with similar chemical properties are arranged in vertical columns called groups or families.
Elements in the same family have the same number of valence electrons

11. Periodic Table cont.
Group 1 the alkali metals, group 2 the alkaline earth metals and group 17 the halogens are the most reactive elements
Group 18, the noble gases are the most nonreactive

12. The elements neon and argon are not reactive
The elements neon and argon are not reactive. Which hypothesis BEST explains this?
They are not stable atoms.
They are not readily available on Earth.
They tend to give up all of their valence electrons easily.
They have the maximum possible number of electrons in their outermost shell.

13. Periodic Table cont.
When a metal and nonmetal react with each other, the metal forms a positive ion (cation) and the nonmetal forms a negative ion (anion).
Metals in group 1 lose one electron to form an ion with a charge or valence number of 1+

14. Periodic Table cont.
Group 2 metals lose two electrons to form ions with a 2+ charge
Group 16 nonmetals gain 2 electrons to form ions with 2- charge
Group 17 nonmetals gain 1 electron to form ions with 1- charge

15. Bonding
When a metal and nonmetal give and take electron(s) with each other, they form ionic bonds
The subscripts in a binary ionic compound depend on the charges of the elements involved – they MUST BALANCE
Ex. Mg2+ and N3- will form Mg3N2
The metal is listed first, then the nonmetal with – ide suffix: magnesium nitride

16. A student is modeling the units in the formula for aluminum sulfide using the spheres shown below to represent aluminum (Al) and sulfur (S) atoms. Which model correctly shows a stable ionic compound for aluminum sulfide?

17. Bonding cont.
When two nonmetals share valence electrons, they form covalent bonds
The names of binary covalent compounds include prefixes to show the number of atoms of each element in the compound, and the –ide suffix
Mono- is never used for the first element

18. Forces at work in an atom
Gravity
Electromagnetic
Weak force
Strong force

19. Radiation –the emission of energy as electromagnetic waves or moving particles
Occurs in massive elements with unstable nuclei
Alpha – large particles (He nuclei) – can be stopped by a sheet of paper
Beta – consist of electrons (e-) – more penetrating than alpha – block of wood
Gamma – extremely energetic form of light – concrete or lead

20. Radioactive Decay cont.
Radioactive elements have specific rates of decay
Measured in half-life – the time required for one-half of the atoms to undergo decay

21. The half-life of cadmium-109 is 464 days
The half-life of cadmium-109 is 464 days. A scientist measures out a 256.0g sample. Approximately how many grams of cadmium-109 would remain after 1,392 days?
32.0g
64.0g
2,048.0g
1,024.0g

22. Nuclear Fission
Occurs when unstable nuclei decay spontaneously or when they are bombarded by neutrons resulting in two smaller atoms and the release of energy

23. A student is modeling the fission of uranium nuclei
A student is modeling the fission of uranium nuclei. The student started the model as shown in the diagram. Which TWO particles should the student add to the right-hand side of the model to complete the fission reaction?

24. Nuclear Fusion
Fusion occurs when low mass nuclei (such as hydrogen) collide and combine to form nuclei with greater mass

25. A group of students proposed four different models to show the fusion of hydrogen to form helium. Which model shows the process of nuclear fusion?

26. Nuclear Chemistry video

27. Make sure to make note of any questions you have on the content or the review questions so we can maximize our time!