Pg 29 Header: I can calculate mass number for isotopes Title: Isotopes

What is an isotope? Two atoms with equal protons but different neutrons are called isotopes of each other. All atoms in existence are isotopes! Some isotopes are just more common than others.

X A Z Isotope Notation Mass number = number of protons + number of neutrons A X Element symbol Z Atomic number = number of protons

X A Z A – Z = number of neutrons Number of neutrons = Mass Number – Atomic Number

Hyphen Notation Write out the name of the element, then add a hyphen (-), then the mass number. Example: Chlorine-35

Isotopes Isotopes: atoms with equal protons but different number of neutrons DRAW this in your notes – use colored pencils

Isotope Notation Write each of these cases, in isotope notation under the picture that you draw!

Hyphen Notation Now, write the hyphen notation for the three isotopes of hydrogen in your drawings above. Isotope Notation Hyphen Notation hydrogen-1 hydrogen-2 hydrogen-3

U U 235 92 238 92 Mass number Atomic number Mass number Atomic number Examples of uranium isotopes: Glue in and answer questions! U 235 92 U 238 92 Mass number Atomic number Number of protons Number of neutrons Mass number Atomic number Number of protons Number of neutrons

U U 235 92 238 92 Mass number 235 Atomic number 92 143 Mass number 238 Now, check your answers! U 235 92 U 238 92 Mass number 235 Atomic number 92 Number of protons Number of neutrons 143 Mass number 238 Atomic number 92 Number of protons Number of neutrons 146 Isotopes of any particular element contain the same number of protons, but different numbers of neutrons.

Pg 30: I can characterize ions Title: Ions

Ions Ions are charged particles. They are positive or negative Ions Ions are charged particles. They are positive or negative. Different number of p+ and e-

Anions & Cations Cation: A PAWsitive ion. Anion: A negative ion. Example: Na+1 Anion: A negative ion. Example: Cl-1

Ions’ charges come from changes in ELECTRONS only! Ions have charges! Draw these examples of ions in your Comp Book! Charge: -1 +1 Ions’ charges come from changes in ELECTRONS only!

Final Facts All atoms and ions are isotopes. All ions are charged. All atoms are neutral. Ions are also isotopes!

Worksheet Go back through your petri dishes from yesterday Fill in ALL the boxes

Ion Practice Do this in your Comp Book to practice Example #1: How many p+ and e- does each have? Ni Sr +2 Br -1

Heavy vs. Light Isotopes To determine if an isotope is heavy or light…. Compare the mass number to the average atomic mass on the periodic table for that element. If the mass number is higher, it is HEAVY If the mass number is lower, it is LIGHT If the mass number is within .5 amu of the atomic mass, it is AVERAGE

Heavy vs. Light Isotopes Example 1: Calcium-41 Example 2: Sodium-22 Example 3: Chromium-52