Notes lab 04b the atom structure

Each element is pure, it has its own unique type of atom, which is identified by its atomic number. (1 – 118)

Everything is made up from these elements or combinations thereof

The smallest particle of an element is an atom. The atom is the basic building block of matter

It usually has no electric charge or has a neutral charge

The atom is actually mostly empty space!

The atom consists of 3 subatomic particles that differ in their location, electrical charge and relative mass.▪Proton▪ Neutron▪Electron

The Proton Found in the nucleus of the atom.

The largest particle, almost equal in mass to the Neutron.

It is a positively charged particle (p+)

The Neutron Also found in the nucleus. Almost equal in mass to the Proton.

It has no charge (n0) it is NEUTRAL

The Electron Found outside the nucleus in the ”Electron Cloud” and also in the outermost energy level “The Valence”

Much smaller than the proton or neutron, having almost no mass.

It is negatively charged (e-)

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The outer energy level electrons for each type of atom. Number from 1 – 8.

They create a type of “shell” around the atom that allows for atomic bonding.

At 8 valence electrons, an atom can not bond

Every atom has a name and corresponding number called “The Atomic Number” on the “Periodic Table of Elements”

The Atomic Number is equal to the number of protons in the atom’s nucleus.

It can’t ever change

The number of Protons in the nucleus is also (99.99% of the time) the same as the number of total electrons in the electron cloud + valence

This is why atoms have no electrical charge.

An equal number of positive and negative charges produces a neutral charge

The mass of an atom (Atomic Mass) comes from the Nucleus of the atom

In the nucleus, one will find all the protons and possibly neutrons

Each proton has a mass of 1 Atomic Mass Unit, each Neutron also has a mass of 1 AMU

The list of atoms and their properties are presented on the Periodic Table of Elements

Each atom has a box with a unique symbol to represent it on the Periodic Table

The Symbol uses a capital letter and sometimes a lower case letter to represent each atom

(Average)

Atomic Mass

How do I find out the number of valence electrons? Just look at the Group/Family number’s singles digit.

The one’s digit in the group number is the number of valence electrons for each atom in that group/family

How do I find the number of Neutrons in the nucleus of an atom? Round the atomic mass to an even number (Mass Number)

Subtract the atomic number from the mass number