Matter

Matter Matter is everywhere. It is anything that has mass and takes up space. Examples: books, paper, oxygen, soup, hands, etc. All matter is made of elements. Elements are materials that cannot be broken down into anything simpler. There are more than 112 elements.

Metals, nonmetals, and metalloids All elements are metals, nonmetals, or metalloids. Metals – shiny, conduct heat and electricity, and bend easily Examples: Silver, gold, platinum, titanium Nonmetals – dull, poor conductors of heat and electricity, and brittle Examples: oxygen, hydrogen, helium Metalloids – some properties of metals, some properties of nonmetals Examples: silicon, arsenic

Atoms An atom is the smallest unit of an element that retains the properties of that element. John Dalton, in 1803, proposed that elements are made of tiny particles. These particles we know today as atoms.

Inside atoms Atoms are made of even smaller particles. Atoms contain protons, electrons, and neutrons.

Protons Protons- a particle with one unit of positive electric charge. Atomic number- the number of protons in an atom. The atomic number determines which element it is.

Neutrons A neutron is a particle with no electric charge. It is neutral.

Electrons Electrons are particles with a negative charge. They move within the space outside the nucleus.

Atomic Mass If you add up the mass of all the protons and neutrons in an atom, you have found the atomic mass!

Compounds and molecules A compound forms when two or more elements combine Compounds have properties that are different from the original elements! Examples: salt (sodium chloride) and rust (iron oxide) A molecule forms when two or more atoms join together and share electrons Example: water

What properties are used to classify books in a library? They are classified by: Fiction and nonfiction Nonfiction by subject matter Fiction by author’s last name

What properties are used to classify animals? Vertebrates or invertebrates How they reproduce Cold-blooded or warm-blooded

How do you think elements are classified? They are classified according to their properties.

What properties are used to classify elements? They are classified by: Whether they are reactive Whether they are solid, liquid, or gas at room temperature Whether they are metal, metalloid, or nonmetal

The Periodic Table of Elements Each element has a symbol. The symbols for most elements are one or two letters. The first letters are always capital. Second letters are never capitals. In 1869, Dmitri Mendeleev made element cards. He ordered the elements from lightest to heaviest. He found that the elements’ properties repeat in cycles. He made the cycles of elements into rows in a table. Mendeleev’s table is called a periodic table because the properties repeat in cycles.

The periodic table

How do the particles in your desk move? They vibrate in place. How do the particles of water from the drinking fountain move? They flow past each other. How do particles in the air move? They move past each other very easily.

Forms of Matter Three states of matter: solid, liquid, and gas

Forms of Matter Solids have a definite shape and a definite volume no matter what container they are in. Can only change by breaking or heating etc. Particles have very little freedom to move

Forms of Matter Liquids have a definite volume, but not a definite shape, Shape depends on container. Particles move more freely than in a solid.

Forms of Matter Gas particles are not close together and can move very freely. Gas does not have definite volume or definite shape.