Review PowerPoint Units 1 and 2

Atoms Atoms are the basic particle from which all elements are made Atoms make up everything, your body, the air, the ground An element, is one or more atoms that cannot be chemically broken down into simpler substances

The Periodic Table All of the elements that have been discovered are found on the periodic table of elements Remember the periodic table of elements was first developed by Dimitri Mendeleev The current periodic table is arranged by increasing atomic number

Atoms are made up of three parts Subatomic particles – are the tiny parts that make up atoms, there are three: protons, neutrons, and electrons What you need to know… Location – 1. Nucleus 2. electron cloud Charge – positive, negative, neutral Mass – 1 AMU OR much smaller than that

Protons Super Important!!! Because, they tell you what type of element it is. Protons never change – Every atom of one element, ALWAYS have the same number of protons Carbon has 6, Helium has 2, Lithium has 3 Positive, in the nucleus, 1 AMU

Electrons In a neutral atom, the number of electrons is the same as protons The electron cloud is the entire area where electrons might be found Valence electrons are the electrons in the outside energy shell = chemical properties Negative, electron cloud, 1/2000 AMU

Neutrons Do Nothing!!!!! They just add to the mass Isotopes are atoms of the same element with different numbers of neutrons On the STAAR – They will try to trick you about neutrons The number of neutrons in an atom is figured out by taking the atomic mass (Labeled) and subtracting the atomic number (Labeled) On the STAAR – they will give you the mass, and the atomic number (number of protons) – use what you are given!!! Nucleus – Neutral – 1 AMU

THE PERIODIC TABLE IS A MAP How to remember the difference between horizontal and vertical Groups – vertical lines in the periodic table – groUP Periods – horizontal lines in the periodic table Periods are at the end of sentences………. Sentences run from left to right

groUPs The groups of the periodic table, have elements with the same chemical properties They all have the same number of valence electrons The empty spaces are there so the elements with similar numbers of VE- can stay in the same group

Numbers of VE- Group 1 = 1 Group 2 = 2 Groups 3-12 are crazy = 1 OR 2

8 is GREAT!!! All atoms want a full outside shell of electrons 8 makes a full outside shell This is why the group 18 elements – the Noble Gasses – don’t react All other elements want to gain or lose electrons to get a full outside shell

Drawing atoms based on element tags Remember the atomic number tells you how many protons and electrons to draw The atomic mass – the atomic number tells you how many neutrons to draw

Draw this atom

Draw this Atom

Draw this atom

Draw this atom

Draw this atom