Gr. 9 Science
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What is the 2, 8, 8, rule in bohr diagrams?
There are 2 electrons on the first shell, 8 electrons on the second shell, and 8 electrons on the first shell.
The basic unit of a chemical element.
The simpliest form of a substance.
A homogeneous mixture or two or more substances.
Two or more substances mixed together.
Define pure substance.
A substance that contains only one kind of matter.
Composed of 2 or more elements in a fixed ratio.
Define physical change.
No new substance is formed, just a change in physical appearance.
Define chemical change.
Always causes at leat one new substance to be formed with new properties.
Define chemical symbol.
A chemical symbol is the 1 or 2 letter international code for a chemical element.
What is the mass for each charge of an atom?
Proton - 1
Neutron - 1
Electron - 0
How do you calculate how many protons and electrons there are in an atom using the atomic number?
How do you calculate how many neutrons there are in an atom using the atomic number and the atomic mass?
Neutrons=atomic mass-atomic number.
How is the periodic table organized?
The periodic table is organized by their atomic number.
What are the names of the families on the periodic table?
1. Alkali metals
2. Alkaline earth metals
3. Transition metals
6. Noble gases
7. Rare earth metals
Where are the metals located on the periodic table?
Metals are located on the left side of the "staircase."
Where are the non-metals located on the periodic table?
Non-metals are located on the right side of the periodic table.
Where are the metalloids located on the periodic table?
Metalloids surround the "staircase."
What is the reactivity of Alkali metals?
Alkali metals are very reactive expecially with water.
What is the reactivity of Alkaling earth metals?
Alkaline rare earth metals are reactive but less that Alkali metals.
What is the reactivity of Transition metals?
Can bond with many element in a variety of shapes.
What is the reactivity of Rare earth metals?
Some are reactive.
What is the reactivity of metalloids?
They have some properties of metals and some properties of non-metals.
What is the reactivity of Halogens?
Halogens are very reactive and are often bonded with elements from the Alkali metals.
What is the reactivity of Noble gases?
They do not interact with other elements to form compounds.
Define chemical formula.
A chemical formula is the representation of a substance using symbols.
Carbon - 12
Hydrogen - 24
Oxygen - 12
Gr. 9 Science