There about 90 naturally occurring elements and another

There about 90 naturally occurring elements, and another 25 synthetic elements. Based on their properties… elements can be divided into 3 classes

Most of the elements are metals Most are silver/grey in colour and shiny All good conductors of heat and electricity Highly reactive with other substances. Most are solids at room temp Are malleable (shapeable) and ductile (can be stretched)

Only 17 elements are non-metals Grouped together because they lack resemblance to metals…not because they are similar to each other Exist as solids, liquids or gases at room temperature Lots of variation in colour

All the remaining elements They have properties that fit with BOTH metals AND non-metals They are considered the intermediate between the two ends of the Periodic Table Some conduct electricity, but not very well, or under specific conditions (called semiconductors)

Group IA: Alkali Metals Group IIA: Alkaline Earths Group VIIA: Halogens Group VIIIA: Noble Gases Metals: Nonmetals: Lanthanide Series: AKA rare earths Actinide Series: AKA transuraniums

The periodic table organizes ALL the elements according to their chemical properties. Notice METALS are on the LEFT SIDE and CENTRE of the table. The NON-METALS are on the FAR-RIGHT. (With one exception – HYDROGEN – which is located on the left side since it often behaves like a metal in chemical reactions) The METALLOIDS are between them, located right along the STAIRCASE LINE.

Atomic Number Chemical Symbol Chemical Name Atomic Mass Charge in Compound Name in Compound

The periodic table is organized into rows and columns. Each horizontal line (or row) is called a period. Represents electron arrangement. 1 2 3 4 5 6 7

Each vertical column forms a group (or family) of elements numbered 1 to 18. The chemical families are groups of elements that have similar chemical and physical properties. 1 18

GROUP 1 – ALKALI METALS - They are soft, shiny and silver in colour - They are the most reactive elements - Francium is the most reactive metal Fr Sodium

Magnesium GROUP 2 – ALKALINE EARTH METALS - They are shiny and silver in colour, but not soft - They are the second most reactive group - Called “Alkaline" earth metals because they form "alkaline" solutions (OH) when they react with water, so they have a p. H greater than seven and are basic.

Fluorine GROUP 17 – HALOGENS - These elements are poisonous and react readily - Colored non-metallic elements, colour gets deeper as you move down the group - Fluorine is the most reactive non-metal F

Neon GROUP 18 – (INERT) NOBEL GASES - These elements are very unreactive

The Staircase separates the metals from the non-metals NON-METALS

An atom is the smallest part of an element that still has the properties of that element PROTONS (+) ELECTRONS ( - ) NEUTRONS (no charge)

The Atom has the same # of protons and electrons. Atomic Number = number of protons and electrons. Number of Neutrons = Atomic Mass – Atomic number Atomic Number p+ and e– Atomic Mass no = Atomic Mass – Atomic Number p+ = 35 e– = 35 no = 79. 90 – 35 = 44. 90 Round: no = 45

are Atoms from the same element that contain different numbers of neutrons. Notice in the last example…the no = 44. 90 This means that Bromine usually has 45 neutrons , however it can sometimes exist as an isotope with 44 neutrons The atomic symbol is sometimes show with the mass number and the atomic number Using this format, the isotopes for Bromine are: and

Isotopes have the same number of protons but different numbers of neutrons Example: Isotopes of Hydrogen (99% of natural hydrogen is this isotope) Hydrogen (deuterium) found in "Heavy" water (tritium)

1. Aluminum Atomic Number = 13 Atomic Mass = p+ = 13 e– = 13 26. 98 no = 26. 98 - 13 no = 13. 98 Round = no = 14 2. Lead Note: As an isotope, Aluminum most often exits with 14 neutrons, but sometimes has 13!

Electrons (-) take up most of the volume of an atom (like 99. 9% of it!) and they occupy specific energy levels. An energy level is a space near the nucleus that may be empty OR may contain electrons. Electrons in energy levels near the nucleus have the lowest Energy energy. Levels Electrons that are farther away from the nucleus have the more energy. e- Nucleus

* Maximum number of electrons held by each energy level Orbits or Energy Levels Energy levels can be empty, partly filled or completely filled! the rest 18 e 8 e 8 e 2 e- Valence electrons – the electrons in the outermost energy level Nucleus

Metals and non-metals can find a mutual solution to their electron's problem!

The Rule of Eight states that atoms bond in such a way as to have eight electrons in their valence energy levels. This is another way to say that atoms tend to be stable with full outer energy levels. How many electrons do we need to gain or loose to stay stable? ? ? fluorine neon magnesium

ü Read pages 28 – 39 ü A 2. 1 Check and Reflect page 39 #’s 1 – 13