Chapter 2 Topics:

Elements and the Periodic Tablehttp://www.youtube.com/watch?v=1PSzSTilu_sCan you find the halogens? Alkali metals? Noble gases? Transition metals? Alkaline earth metals? Lanthanides and actinides? Metals? Nonmetals? Semimetals or metalloids?http://ed.ted.com/periodic-videos

*Balancing Equations

What coefficients balance this equation:

Mg + Al2S3 → Al + MgS

*Types of ReactionsClassify the reaction type above.

*These two topics will be on the 2b Exam, not the 2a Exam!

Particle Charge Mass Location

Electron -1 1/1800 Outside the nucleus

Proton +1 1 Inside the nucleus

Neutron 0 1 + 1/1800 Inside the nucleus

Subatomic Particles!

Atomic number is the number of protons.

This tells WHAT element it is!

The number on thePeriodic table is theATOMIC WEIGHT.This is an average

mass of all theISOTOPES thatoccur in nature.

Atomic mass or mass number is a WHOLE number that must be rounded from the number on the periodic table. It is the number of protons + the number of neutrons in an atom of the element.

Isotope Notation!

Isotopes are atoms of the same element that havedifferent MASSES. They have the same number

of PROTONS, but different numbers of NEUTRONS.

Isotopes of an element have

the same physicaland chemical

properties. Theyonly have different

MASSES!

4020

Ca How many protons? What is the atomic number? What is the mass number? How many neutrons? How many electrons? (Hint: All atoms must be neutral!)

21Ne How many protons? How many neutrons? How many electrons?

199X How many protons? How many neutrons?

What element is this?

An isotope of an element has 3 protons and 4 neutrons. Write its isotope notation.

20 protons, atomic number 20, mass number 40, 20 neutrons, 20 electrons

10 protons, 11 neutrons, 10 electrons

9 protons, 10 neutrons, Fluorine

73Li

ATOMIC WEIGHT

Lithium exists as two isotopes: lithium-7 and lithium-6

Lithium-7 has a mass of 7.015 amu and makes up 92.58% of lithium

Lithium-6 has a mass of 6.015 amu and makes up 7.42%

To calculate the average atomic mass of lithium, multiply the mass of each isotope by its abundance, then add these 2 values to each other

What is the atomic weight of lithium (on the periodic table)? Which isotope is more abundant, lithium-6 or lithium-7?

Mass Defect

There's actually one more reason why the mass isn't a whole number.... recall that the mass of a neutron isn't

exactly 1 amu. And when protonsand neutrons stick togetherto make a nucleus, a small

amount of mass is converted to energy, making

a very strong bond calledstrong nuclear force.

E=mc2

IONS*

Atoms are neutral because they have the same number of protons and electrons.

When an atom loses electrons it becomes a positively charged ion called a cation.

When an atom gains electrons it becomes a negatively charged ion called an anion.

*Ions will be on the 2b Exam *I*

39K+ How many protons does this isotope have?

How many neutrons? How many electrons does this ion have?

16O2-

How many protons does this isotope have?How many neutrons?

How many electrons does this ion have?

19 protons, 20 neutrons, 18 electrons

8 protons, 8 neutrons, 10 electrons