Elements & Compounds

Atom Def: The smallest particle of an element or matter

Atoms are used to create the elements.. Elements are used to create everything in the world.. So far, there are over 100 known elements.

Element Def: A substance made up of only one KIND of atom. In other words, all of its atoms are identical (the same). It is a pure substance.

Gold is an element. An element is a substance which cannot be broken down into simpler substances under normal circumstances. This means that if you break gold down into smaller and smaller pieces, it will still be gold. Gold is made of nothing... but gold.

Gold cannot be broken down into any other substances. The smallest, tiniest piece of gold is an atom of gold. An atom is the smallest unit of an element.

Where do we find the list of all the elements?

Oxygen (65%) Carbon (18%) Hydrogen (10%) THE HUMAN BODY Nitrogen (3%) Calcium (1.5%) Phosphorus (1.0%) Potassium (0.35%) Sulfur (0.25%) Sodium (0.15%) Magnesium (0.05%) Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.70%) Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts)

The Periodic Table Dimitri Mendeleev was the Russian scientist who developed the modern Periodic Table The Periodic Table is an arrangement of all elements in order of atomic number.

What is the chemical formula for water? H2OH2O hydrogen oxygen HH O

This is a molecule of water. Is it a pure substance? NO! Because I can separate it into two kinds of elements. We call these compounds. Compound - a substance made up of more than two or more elements.

Salt is not an element. Salt can be broken down into simpler substances--sodium and chlorine.

Salt is not an element. Salt can be broken down into simpler substances--sodium and chlorine. Salt is made up of more than 1 element. We call that a ____________. compound.

Let’s make models!

Find the element lithium on the periodic table. Tells how many protons are in the atom of lithium Tells the mass of the atom of lithium Is the symbol for lithium.

The symbol for beryllium is A.BE B.Be C.be

What is the symbol for beryllium? Be What do you notice about the first and last letters of the symbol? The first letter is always a capital and the following letters are always small letters.

Why do you think the second letter is not a capital? NACLO NaClO How many elements are shown? Cannot tell Sodium Chloride Oxygen

Sugar is made up of more than one element, so sugar is a/an A.element B.Mixture C.compound

Salt is made up of 2 elements. So salt is a _______________. Salt is made up of sodium, which has the symbol _______ and chloride which has the symbol __________. We can represent salt with the formula_________. compound Na Cl NaCl In a compound, the different elements are chemically bonded together.

A formula tells us what elements are in matter and how many atoms there are of the element. K 3 CrO 2 3 atoms of potassium 1 atom of chromium 2 atoms of oxygen These atoms are bonded together chemically!

Write down these formulas. Tell what elements they are made up of and how many atoms there are in each substance. H 2 O 2 HCl NaH 2 CO 3 2 atoms hydrogen, 2 atoms oxygen 1 atom hydrogen, 1 atom chloride 1 atom sodium, 2 atoms hydrogen 1 atom carbon, 3 atoms oxygen Why are these compounds? More than 1 type of element is bound together.

Is this a compound? Li A.Yes B.No

Is this a compound? KCl A.Yes B.No

Is this a compound? CO 2 A.Yes B.No

This is a compound O 2. A.Yes B.No

Draw the picture below. Label each of the boxes. The circles represent atoms of an element. Element MixtureCompound

Identify the compounds. O 2 NaCl H CO 2 Li 2