Comparing Kinds of Matter Chapter 5

Lesson 2: Elements

REVIEW Lesson 1

Measures Weight

• NEWTONS

• AND

• POUNDS

The amount of matter in an object

MASS

How strongly gravity pulls on an object

WEIGHT

Measures Volume

• MILILITERS AND CUBIC

CENTIMETERS

Measures how much space matter takes up

VOLUME

Measures Mass

KILOGRAMS

AND

GRAMS

the amount of mass for each cm3 of a substance

Density

Resistance to sinking

• Buoyancy

Imaginary “skin” that rests on the surface of water

• Surface Tension

What forms can matter have?

• Solid

• Liquid

• Gas

Have a definite shape and volume

• Solids

Have an indefinite shape; volume takes the shape of its container

• Liquid

Have an indefinite shape and volume

•Gas

Lesson 2: What is an Element?

• is a material that cannot be broken down into anything simpler by chemical reactions

• chemical element is the simplest form of matter

What is matter made of?

• all matter is made up of the same set of building blocks

Important properties of elements

• state of matter at room temperature (Most elements are solids, some are gases, and a few are liquids)

• Examples:

• Solids: Iron (Fe), Nickel (Ni), Cobalt (Co)

• Liquids : Mercury (Hg)

• Gas: Helium (He), Oxygen (O)

Important Properties of Elements

• the way they combine with other elements (some elements are likely to combine with other elements to form new substances. These elements are more chemically reactive) – Fluorine (F)

elements are of three types:

• metals

• nonmetals

• metalloids

Metals, Nonmetals, or Metalloids

• Metals are elements that share common properties such as shiny, conductivity, flexibility (iron, cobalt, nickel)

• Nonmetals are elements that are dull, poor conductors and brittle

• Metalloids are elements with properties that are in between

Atom• the smallest unit of an element that retains

the properties of that element

• Any element listed on the periodic table consists of atoms. Hydrogen, helium, oxygen and uranium are examples of types of atoms.

What are atoms and molecules made of?

• nucleus is the center of an atom

• the nucleus is made of protons, and neutrons• A proton is a particle with one unit of positive

electric charge (number of protons in an atom is the atomic number)

• A neutron is a particle with no electric charge

• An electron is a particle with one unit of negative electric charge

• Electrons move around in the space outside the nucleus

Molecules• . Molecules are small particles that make up all

living and non-living things

• particles with more than one atom joined together

• most of the atoms in the world exist as part of a molecule, not on their own

• objects in the world are just many molecules grouped together

Example of a Molecule

• Carbon DioxideLess than 1% of the air is carbon dioxide, but it is essential for life. Plants use carbon dioxide to build energy-rich molecules.CO2

1 black carbon atom2 red oxygen atoms

What are the most common elements?

• In space, the most common elements are hydrogen and helium.

• On Earth, elements such as hydrogen and any of these: oxygen, silicon, aluminum, nitrogen, iron, and calcium are among the most common