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