2.1 ELEMENTS

The smallest building blocks of matter are atoms. What is the difference between an atom and an element?

An element is a pure substance that cannot be broken down or separated into simpler substances. An element is a type of atom.

Example: Copper is an element, An atom of copper is the smallest possible piece of copper you can have, that still has all the properties of copper.

CHEMICAL SYMBOLS Each element has a name, but the names are different depending on the language you speak.

Symbols provide an international language so all chemists around the world can share their discoveries. – If symbol is only one letter  capitalized – If symbol is 2 letters  1 st capitalized, 2 nd lower case Eg: Oxygen = O Mercury = Hg

INVESTIGATING THE STRUCTURE OF THE ATOM Every atom is composed of 3 types of particles: – Protons: positively charged – Neutrons: no charge – Electrons: negatively charged Protons and neutrons are found in the nucleus Electrons circle the nucleus in particular energy levels

Rules for atomic particles: 1.# protons = # electrons 2.Atomic number = # protons 3.Atomic mass = the mass of an average atom of an element 4.Ion charge = an electric charge that forms on an ion when it gains or loses electrons.

Assignment: “Learning chemical symbols” worksheet Reading check page 47 CYU page 51 #1-18 “Adopt-an-element” project

Who created the periodic table? Dmitri Mendeleev He arranged it by grouping elements with similar properties together The periodic table contains an amazing amount of information

Info on a square in the Periodic Table: Some elements have multiple ion charges as they form ions in more than one way.

Trends in the periodic table: Elements are arranged in order of atomic number THEY ARE NOT ARRANGED BY ATOMIC MASS!!

Trends in the periodic table: Elements on the LEFT side of the table mostly form POSITIVE ions – This means they LOSE ELECTRONS

Trends in the periodic table: Elements on the RIGHT side of the table mostly form NEGATIVE ions – This means they GAIN ELECTRONS

Trends in the periodic table: Elements in the same column usually have similar ion charges.

Trends in the periodic table: Metals, Non-metals and Metalloids… Elements are clumped in groups that have similar properties Table 2.2 (pg.55) shows the properties that each of these groups have in common.

Trends in the periodic table: Within each of these groupings are columns of elements with very similar properties. – These are called families

Assignment: Reading Check page Worksheet Complete “Adopt an Element” research