Chemistry:Atoms and Molecules Notes

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Definitions

Atom - The smallest unit of matter that can exist of an element.

Compound - A molecule containing two or more different atoms bound together.

Element - A fundamental substance that has a unique atomic number on the periodic table.

Isotope - A different form of an element that varies by the number of neutrons in the nucleus.

Neutron - An uncharged atomic particle of mass 1.67493x10-27 . It resides in the nucleus.

Nucleus - The small, dense central region of an atom around which electrons orbit. The nucleus is made up of protons and neutrons.

Proton - A positively charged particle of mass 1.6726x10-27 . Protons reside in the nucleus.

Valence electrons - The electrons in the outermost energy shell of an atom. The configuration of these electrons determine the chemical properties of the element.

Valence shell - The highest energy shell in an atom, containing valence electrons. All interactions between atoms take place through the electrons of the valence shell.

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Protons, Electrons and Neutrons[Subatomic particles]

Protons

Charge: +1

Mass: 1

Electrons

Charge: -1

Mass: 1/1840

Neutrons

Charge: 0

Mass: 1

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Atoms

1)Definition:Atom - The smallest unit of matter that can exist of an element.

2)Chemical Symbol:X-A

A:Nucleon number

X:Symbol of element

Protons=Electrons

Nucleon:Protons+Neutrons

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Molecules

1)Definition: Molecule-A group of 2 or more atoms chemically combined together

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Difference between Atom and Molecule

Atoms: Like Lego

Molecule: Things that we make using Lego blocks

https://www.youtube.com/watch?v=RbbOBPfH_uk (Embed)

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Ions

1)Definition: A group of atoms or an atom with electrical charge.

2)Neutral: No charge

3)Cation: Positive ion---CATion PAWSitive

4)Anion:Negative ion---A Negative Ion

5)Polyatomic ion:A group of atoms that have a charge

Metals

Lose electrons

Form positive ions

Non metals

Gain electrons

Form negative ions

https://www.youtube.com/watch?v=WWc3k2723IM (Embed)

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Isotopes

1)Definition: Different versions of a certain kind of atom

https://www.youtube.com/watch?v=EboWeWmh5Pg (Embed)

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The Periodic Table

Groups:Columns

Periods:Rows

**For groups,must write in Roman numerals

Group 7-Ide for metal-non metals

https://www.youtube.com/watch?v=yADrWdNTWEc (Embed)

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Extra Notes