What Matter is Composed Of?
The smallest unit of an element that still has the properties of that element.
Atom
A substance that contains only one kind of atom.
Element
The temperature at which a substance changes from a solid to a liquid.
Melting Point.
How are protons and neutrons alike?
Both are found in the nucleus
Grinding chalk into a powder is a chemical change, or a physical change.
Physical Change
The number of protons in an atom is its....
Atomic Number
A substance made of atoms of two or more elements that are chemically combined.
Compound.
State of matter which is made up of charged atoms, uncharged atoms, and electrons
Plasma.
Remains Constant
State of matter that makes up 99 percent of all matter in the universe. Formed when gas gets very hot and it's atoms gain so much energy that they lose on or more electrons.
Plasma.
Subatomic particle that has a negative charge.
Electron.
A table arranged by atomic number
Periodic Table.
A molecule is a group of two or more atoms held together by chemical bonds.
Molecule
How do the freezing point and the melting point of a substance compare?
The melting point is higher than the freezing point.
How many elements on the periodic table are found naturally?
90 or 94.
Elements that conduct heat and electricity well, are malleable, and most are shiny.
Metals
True or False, melting point is always achieved at a higher temperature than boiling point.
False
How many elements does a mixture of copper, iron, bromine, phosphorus, hydrogen, oxygen, thallium, zinc, polonium, xenon, and krypton have?
11
State of matter that has no definite shape or volume.
Gas
Scientist who suggested that electrons orbit at different distances from the nucleus. (Fairly close to correct).
Niels Bohr
Atoms of carbon bonded with atoms of hydrogen, oxygen, nitrogen, sulfur, chlorine and other elements. (Originally obtained from living things.)
Organic Compounds
Substances can change from a solid directly to a gas without ever becoming a liquid. This process is called...
Sublimation
What can you infer about two substances that have the same atomic number, but different atomic masses?
That they have a different number of neutrons.
Element with the atomic number of 2.
Helium