6 th Grade Science

Matter 5.4The student will investigate and understand that matter is anything that has mass, takes up space, and occurs as a solid, liquid, or gas. Key concepts include atoms, elements, molecules, and compounds 6.4The student will investigate and understand that all matter is made up of atoms. Key concepts include atoms are made up of electrons, protons, and neutrons; atoms of any element are alike but are different from atoms of other elements; elements may be represented by chemical symbols; two or more atoms may be chemically combined; compounds may be represented by chemical formulas; chemical equations can be used to model chemical changes; and a limited number of elements comprise the largest portion of the solid Earth, living matter, the oceans, and the atmosphere.

Matter (anything you can touch) is composed of atoms. Matter comes in 5 forms but the most common are solids, liquids and gases. Matter can be described and identified by physical and chemical properties.

The most common are solids, liquids and gases.

 There are 2 main locations in an atom: nucleus (the center with most of the mass of the atom) electron cloud (surrounds the nucleus)  There are 3 subatomic particles in an atom: subatomic means smaller (than the atom itself) 3 particles = protons, neutrons and electrons the numbers of these particles make atoms  different from one another.

Atoms are the smallest particle of an element that retains its identity in a chemical reaction.

Not very big. You’d need special microscopes to see them.

 ATOMS ARE MADE UP OF SUBATOMIC PARTICLES

Atoms are made of even smaller particles called subatomic particles. Electrons Protons Neutrons

Negatively charged subatomic particles. They are 1,000 times smaller than a proton. Electrons are found in clouds that surround the nucleus but because they move so quickly, it is impossible to see where they are at a specific moment in time.

In the world of electronics these very tiny particles stream through wires and circuits creating currents of electricity that power computers, lights, radios and other appliances.

Protons are positively charged subatomic particles. Inside the proton are even smaller particles called quarks. Jefferson Lab in Virginia was built to study these quarks in 1968.

Neutrons are subatomic particles with no charge. Their mass is nearly equal to the proton. Neutrons are related to the radioactive properties of atoms.

The nucleus of the atom is made of protons and neutrons. The electrons are in constant motion around the nucleus.

Democritus Was a greek philosopher who believed that all matter was made up of a smaller particle called the atom.

John Dalton ( ), a scientist, studied the ratios in which elements combine and the result was Dalton’s atomic theory.

John Dalton was a scientist who postulated that All elements are composed of tiny particles called atoms. Atoms of the same element are identical. Atoms of different elements are different

Dalton’s Theory states: All elements are composed of tiny particles called atoms. Atoms of the same element are identical. Atoms of different elements are different.

Dalton’s Theory states: Atoms of different elements can physically mix together or chemically combine in simple whole number ratios to form compounds.

Dalton’s Theory states: Chemical reactions occur when atoms are separated, joined, or rearranged. Atoms of one element are never changed.

THOMSON MODEL - THE FRUITCAKE 1897 HE DISCOVERED THE ELECTRON. HE WAS WRONG TO BELIEVE THAT ELECTRONS WERE SCATTERED THROUGHOUT THE ATOM LIKE PLUMS IN A PUDDING.

 Atoms are made of mostly space.  The center of the atom has a positive nucleus.

Rutherford changed how people thought about atoms when he shot rays through extremely thin gold foil. He concluded that most the of alpha particles pass through an atom because it is mostly empty space. A few particles were deflected because of a positive charge from the nucleus that pushed them.

BELIEVED ELECTRONS MOVE IN THEIR OWN PATHS ON A CERTAIN ENERGY LEVEL AWAY FROM THE NUCLEUS. ELECTRONS CAN JUMP FROM ONE ENERGY LEVEL TO ANOTHER LIKE PLANETS ORBIT THE SUN….

PRESENT ATOMIC MODEL A CLOUD-LIKE REGION WHERE THE ELECTRON IS LIKELY TO BE FOUND. IT CAN NOT SAY WITH ANY CERTAINTY, WHERE THE ELECTRON ACTUALLY IS AT ANY POINT IN TIME, YET CAN DESCRIBE WHERE IT OUGHT TO BE.  Werner Heisenberg was really the person that determined that the only way to describe the location of electrons is as a probability distribution, and this led to the idea of an "electron cloud" where you can only talk about the relative probability of find an electron in a certain volume.

The atomic number of an element is the number of protons in the nucleus. Hydrogen (H) has 1 proton so its atomic number is 1 All Oxygen atoms (O) have 8 protons, so the atomic number of Oxygen is 8.

The mass of an atom is the total number of protons and neutrons in an atom. Electrons are so small they don’t count towards mass. Carbon (C) has 6 protons and 6 neutrons so its mass number is12.

Helium (He) has 2 protons and 2 neutrons so its mass number is 4.

The number of neutrons = Mass number - Atomic number OR Atomic number + number of neutrons = mass

Elements are the building blocks of all matter. A limited number of basic elements make up our universe. Up to this point in time we have discovered/created over 100. Try this quiz from the Jefferson lab roperties_and_changes.html

If everything is made of atoms, why are some elements gases, others solid and some liquid? Atoms differ from each other by the number of protons, neutrons and electrons. This in turn causes each element to be different. The number of protons is the final determining factor.

Atoms prefer to have full shells (parts of the electron cloud.) Its rather like needing 5 people for a basketball team or 11 to play football. Atoms with too many electrons (one or two extra) give them up while those close to having a full shell look for atoms who will give them one or two. This is called ionic bonding

Sometimes atoms share electrons – this is called covalent bonding. This would be like two coaches sharing an athlete. Sometimes the athlete would play basketball, sometimes play football. Electrons move so quickly, it is almost like they can play football and basketball at the same time.

Elements are organized on the periodic table according to their structure. Carbon, hydrogen, oxygen and nitrogen are the most common elements in our world.

A table to hold punctuation like periods and commas? A place where atoms periodically have picnics? An organized chart of the elements?

An organized chart of the elements

Carbon, hydrogen, oxygen and nitrogen are the most common elements in our world.

Ionic bonding is when atoms with too many electrons (one or two extra) give them up while those close to having a full shell look for atoms who will give them one or two.

Jefferson Lab s.html Chem4kids ml Quia matching game

Quia rags to riches game (like Millionaire) Another rags to riches Atomic structure jeopardy Atoms and molecules cloze activity

Quia quiz on Atom and Periodic Table Review All about atoms Chem4kids structure of the atom truct/index.html