Matter and Energy By Sarah Berger

Matter Matter is everything that takes up space. It is every drop of water, Strand of hair, and Every star in the sky. Matter is mass. The bigger pieces of mass are made up of molecules.

Parts of Matter: Molecules Molecules are at least two atoms put together. Many people study molecules and their organization. That is called molecular biology. The atoms in a molecule are held together by bonds. Those bonds are either ionic, or covalent.

Parts of Matter: Atoms Atoms make up everything in the universe. They are in all liquids, solids, and gasses. Atoms are the smallest pieces of matter that can live on their own Atoms consist of three main parts: Electrons Protons Neurons

Electrons Electrons have a negative charge They are.002% the size of the smallest atom electrons have the same weight of one proton. Electrons are arranged in shells. The shells circle the nucleus.

Protons Protons have a positive charge. They are almost 2000 the size of an electron. Protons are located in the nucleus of an atom. Nothing was thought to be smaller than a proton, until quarks were discovered. There are three quarks in every proton.

Neutrons Neutrons have no charge. They are neutral. They are almost the same size as protons. Neutrons are located in the nucleus of an atom. There are also three quarks in each neutron.

Ions An ion is an electrically charged atom. When an atom has one more proton than electron, it is positively charged When an atom has one more electron than proton, it is negatively charged. The number of neutrons does not affect the charge of an atom.

Ionic Bonding Ionic bonding is when an atom gives an electron to another atom to form ions. For example, chlorine needs one more electron, and sodium has one too many. Sodium then loses an electron (but it still has that proton) so it becomes positively charged. Chlorine then gains that electron (but not a proton) so it becomes negatively charged.

Covalent Bonds In covalent bonds, the atoms do not create ions. They just share the electrons. An example would be with water. Oxygen needs two more electrons. Hydrogen only has one, so it can’t give it up. Since oxygen needs two, there is room for two hydrogen atoms in this water molecule. That is why it is called H2O.

More About Atoms Every atom [or element] has a number. Its number is determined by how many protons it has. It could also be determined by how many electrons it has (since elements have the same number of electrons as protons). Every atom [or element] has a weight or mass. The atomic weight of an element is how many neutrons it has added to its atomic number.

More About Atoms Most atoms have multiple isotopes. An isotope is an atom whose number of neutrons varies. Atoms of opposite charge are held together by an electrostatic attraction. This is what holds ions together in ionic bonds. Again referencing to the sodium-chlorite bonding, sodium becomes positively charged and chlorine becomes negatively charged. Like magnets, they stick together.

More about Molecules Molecules stick to surfaces. That is why nothing is floating around. It is called adhesion. Most molecules of the same substance stick together. That is called cohesion. Some molecules are hydrophilic. They are water loving. It is a term applied to molecules that can form a bond with water. Other molecules are hydrophobic. They are water fearing. It is a term applied to molecules that can not form a bond with water.

Gases Gases [like everything else in the universe] are made up of mass. They are different from liquids and solids in the fact that they are not very dense at all. That is the reason we can move our hands through the air with ease. There are fewer molecules per square centimeter. Gases are free to move around, so it is very hard to contain them. They can escape from the smallest holes and cracks.

Liquids Liquids are more dense than gases, but not as dense as solids. Liquids take no specific shape. They form to the container they are in. They can not be condensed. Part of that is due to viscosity –the thickness of liquids.