Atoms and Matter

Atom

basic unit of matter - make up living things

Atoms are made up of:

even smaller particles that make up atoms (subatomic particles)

What are those subatomic particles:

Protons, Nuetrons, Electrons

Center of an atom:

Nucleus

Nucleus contains:

protons and neutrons

Proton has a ___ charge and a neutron has a ___ charge:

positive, neutral/no charge

An electron is:

negatively charged particle (-), smaller than a proton, and found surrounding the nucleus in shells

Electrons are always in

motion

First shell:

2 electrons

Second shell:

8 electrons

Third shell:

18 electrons

Atoms are as _ cancel out.

neutral - positive and negative charges

Element:

pure substance consisting of ONE type of atom

An element is often represented by

one or two letter symbols (ex: C = carbon, CL = chlorine, 0= = oxygen)

Atomic Number:

total number of protons in an element

What can the atomic number tell us?

This can tell you the # of the rest of the particles in the atom

Atomic mass/mass number:

total number of protons + neutrons

A valence shell is:

The outermost shell of an atom

What does the valence shell want

8 electrons

Life on earth is called

carbon based

Organic compounds ALL have

carbon + hydrogen

6 major elements to life: CHONPS

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfuir

Isotope

atoms that are the same element but differ in the number of neutrons only

In nature, elements combine with each other to

form compounds

Compound:

substance formed by the chemical combination of two or more elements

Most abundant compound in living things

water

Compounds are written in terms of

a chemical formula

What does a chemical formula show us?

what elements are in the compound and how many of each there are

How to read chemical formulas:

fixc this later (ex- H20 = 2 hydrogens and 1 oxygen)

To make compounds, elements must

bond together through one of two main types - ionic or covalent bonding

Ionic bonds

bond formed when one or more electrons are TRANSFERRED from one atom to another

Ions

atoms that have lost or gained an electron

*Lose an electron

positive charge ion (cation)

*Gain an electron

negative charged ion (anion)

Covalent Bond:

bond formed when one or more electrons are SHARED by elements

4 major organic molecules:

Carbohydrates, Proteins, Lipids, Nucleic Acids

(Covalent Bond) Sharing two electrons =

single bond

(Covalent Bond) Sharing four electrons =

double bond

(Covalent Bond) Sharing six electrons =

triple bond

When atoms join together ____, we call these ____ - smallest unit of most compounds

covalently, molecules

On top of the strong bonds (ionic and covalent) ____ interactions are just as important between ___ and _____.

weak, atoms, molecules

Van der Waals forces provide ___ attractions between ____ when they are very close together.

slight, molecules

_____ is also an example of weak interactions/Van der Waals forces.

Hydrogen bonding