Science Grade 6, Elements and Compounds

Created by kjones12345 

Upgrade to
remove ads

elements

pure substances that cannon be broken down into any simpler substances.

lead

composed of the element carbon

water

composed of the elements hydrogen and oxygen. this is an example of a compound.

H2O

This means two parts hydrogen

compound

a sustance formed from the chemical combination of two or more elements.

Aristotle

A Greek philosopher who believed all things on Earth were made of four elements: air, earth, fire and water.

Au

Symbol for the element: Gold

Fe

Symbol for the element: Iron

S

Symbol for the element: Sulfur

Cu

Symbol for the element: Copper

C

Symbol for the element: Carbon

Al

Symbol for the element: Aluminum

He

Symbol for the element: Helium

six elements making up most of the human body

oxygen, carbon, hydogren, nitrogen, calcium, phosphorus

number of elements

about 100

atom

the smallest particle of an element that still has the same chemical properties of the elements.

number of atoms that fit in a space as small as the dot of a letter

millions

Democritus

Greek philosopher that believed matter could be cut into smaller and smaller peices only up to a certain point.

John Dalton

formulated the atomic theory.

atomic theory

matter must be made of tiny particles with spaces between them.

high powered microscope

this is needed to see atoms

atoms

these are mostly empty space

Rutherford experiments

These fired helium atoms at gold foil and found most went through the foil, some bounced back.

nucleus

the center of the atom which contains most of the mass

protons and neutrons

these are the two parts of the nucleus.

neutrons

these have no electrical charge, they are neutral.

protons

these have a positive electrical charge.

atomic number

the number of protons in an atom of an element.

atomic mass

the number of protons added to the number of neutrons.

different number of neutrons

atoms of the same element may have different numbers of these.

isotopes

atoms of the same element that have different atomic masses

electrons

these have a very small mass and a negative electrical charge.

these two parts of the atom have about the same mass

neutrons and protons

number of electronics in an atom

this does not change an atom's atomic number. they have virtually no mass.

these move around the nucleus

electrons

atoms generally have the same number of there

electrons and protons

ion

atom that has a positive or negative charge.

periodic table

a chart which shows the elements in the order of increasing atomic number. It is organized by a) physical properties and b) the number of protons

Dmitri Mendeleev

Russian chemist who developed a periodic table of the chemical elements.

periodic

this work means a repeating pattern.

groups or families

these are the vertical columns of the periodic table

periods

these are the rows of the periodic table.

different groups of elements

metals, nonmetals and metalloids.

metals

these conduct heat and electricity, become shiny when polished, melt at high temperatures and can be easily reshaped.

nonmetals

these have a dull surface, melt at lower temperatures and tend to break when bent.

metalloids

these have some properties of metals and some of nonmetals.

found as combinations of one of more elements

most elements exist in this manner.

shells of bird eggs

contains calcium, carbon and oxygen (Ca, C, O).

citric acid

contains carbon, hydrogen and oxygen (C, H, O).

table salt

contains sodium and chlorine (Na, Cl). Good example of a compound whose properties are quite different from the elements comprising the compound.

chemical formula

a simple way to indicate the composition of elements in a compound.

NaCl

chemical formula for sodium chloride.

CO2

chemical formula for carbon dioxide. Two parts oxygen for one part carbon.

A chemical formula showing compound with elements in a 1-to-1 ratio. It is held together by their opposite charges.

NaCl

A chemical formula showing compound with elements not in a 1-to-1 ratio

CO2.

molecule

the smallest particle of a compound that still has all the qualities of that compound. Their atoms are so tightly bonded that they act like a single particle.

H2

Hydrogen gas can exist as these types of molecules where two hydrogen atoms join together.

Water molecules

oxygen shares its electrons with hydrogen and this joins the atoms together.

physical properties / number of protons

The factors used to organize the periodic table.

matter

this can be broken down into molecules, elements and atoms.

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set