Science quest 2
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3 subatomic particles and their charge:
Protons (positive) Neutrons (neutral) Electrons (negative)
Where are protons found in an atom?
In the nucleus
Where are neutrons found in an atom?
In the nucleus
Where are electrons found in an atom?
In energy levels (orbitals) around the nucleus
Order of scientists discoveries:
Democritus, Dalton, Thomson, Rutherford, Bohr, Chadwick
Democritus
The indivisible particle . Matter is made of tiny pieces that cannot be broken down.
Dalton
The billiard ball model. Atoms of an element are identical.
Thomson
Chocolate chip cookie model. Atoms are mainly composed of positively charged material in the shape of a sphere.
Rutherford
The nuclear model. Nucleus is surrounded by mostly empty space.
Bohr
Bohr- rutherford model. Electrons surround the nucleus in specific energy levels.
Chadwick
The planetary model. The nucleus contains neutral particles along with positively charged particles.
Which letter is capital when an element has 2 letters?
The first one
Elements vs Compounds:
Elements: A pure substance that cannot be broken down into simpler substances. Compound: 2 or more elements in a fixed ratio.
Valance electrons
electrons in the outermost level
Group
Vertical column of a periodic table
Period
Horizontal row of a periodic table
How to get neutrons?
Atomic mass - Protons
5 Metal properties
Solid (except mercury) Shiny Good Conductor Malleable Ductile
5 Non- Metal properties
Solid, Liquid, Gas Dull (not shiny) Poor conductors (insulators) Brittle (if solid) Not ductile
Metalloids
In between metals and non-metals. They share properties with metals and non-metals.
What is this element in Standard atomic notation? Li P- 3 E-3 N-4
7 Li 3
Isotope
Atoms of the same element that have different number of neutrons.
How is carbon dating used to determine how old a fossil is?
When something dies, the C-14 starts to go away and the C-12 stays the same. Scientists look at the ratio between C-14 and C-12 and can see how many years have passed since it has dies.