The Atom Date:

Definition of atom: – The basic unit of an element; the building blocks of matter – Have no charge – Composed of 3 subatomic particles Energy levels: These make up the electron cloud

Subatomic Particles ParticleSymbolChargeMass (amu) LocationDetermines protonp+p+ +11nucleusElement identity neutronnono 01nucleusThe particular isotope electrone-e electron cloud If an ion

Electrostatic repulsion and attraction Opposite charges attract – Electrostatic attraction – Protons and electrons – Keeps the electrons from flying away Like charges repel – Electrostatic repulsion – Protons – Why doesn’t the nucleus explode? – The STRONG NUCLEAR FORCE

nucleons

What is the spacing within an atom?

Numbers on the PT What do they all mean?

Key: Atomic number, number of protons Element symbol Element name Average atomic mass The mass calculated by summing the masses of an element's isotopes, each multiplied by its natural abundance on Earth.

Nuclide C 12 6 Name the numbers and tell what they mean Mass number: Sum of #p + and # n o Atomic number: #p + If an atom, then #e - also

Nuclide C 12 6 How many of each subatomic particle?? Mass number: Sum of #p + and # n o Atomic number: #p + If an atom, then #e - also Since the atomic number is 6, there are 6 p +. This is an atom (because there is no charge written in the upper right hand corner) so this atom has 6 e - too! To determine the number of neutrons, subtract the atomic number from the mass number, 12 – 6 = 6 neutrons.

3 Li 7 How many of each subatomic particle??

3 Li 7 How many of each subatomic particle?? Atomic # = # p + 3p +

3 Li 7 How many of each subatomic particle?? 3p + No charge in upper right hand corner, so it is an atom; the number of p + = # e - 3e -

3 Li 7 How many of each subatomic particle?? 3p + Mass number – atomic number = #n o 3e n o

1H1H 3 How many of each subatomic particle??

Atomic # = # p + 1p + 1H1H 3

How many of each subatomic particle?? 1p + No charge in upper right hand corner, so it is an atom; the number of p + = # e - 1e - 1H1H 3

How many of each subatomic particle?? 1p + Mass number – atomic number = #n o 1e n o 1H1H 3

6 C 14 How many of each subatomic particle??

Atomic # = # p + 6p + 6 C 14

How many of each subatomic particle?? 6p + No charge in upper right hand corner, so it is an atom; the number of p + = # e - 6e - 6 C 14

How many of each subatomic particle?? 6p + Mass number – atomic number = #n o 6e n o 6 C 14

What do these all have in common? 6C 6C 14 6C 6C 13 6C 6C 12 They are all C so they all have 6 p +. But they have different mass numbers, meaning they have different #neutrons!

6C 6C 14 6C 6C 13 6C 6C 12 These are Isotopes! Atoms of the same element that differ in the # of neutrons What do these all have in common?

Vocabulary Atom: the basic unit of a chemical element. Average atomic mass: The mass calculated by summing the masses of an element's isotopes, each multiplied by its natural abundance on Earth. Electron: a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids. Electron cloud: an atom model wherein electrons are no longer depicted as particles moving around the nucleus in a fixed orbit but are free to move anywhere within the cloud Energy levels – the various levels (rings) shown around the nucleus of an atom, the number of energy levels an atom has is equal to the period number. Ion – atoms with a charge because it has gained or lost electrons Isotope – two atoms of the same element that differ in the number of neutrons Mass number – the sum of protons and neutron, the number of nucleons present in the nucleus Neutron – a subatomic particle with no charge found in the nucleus of an atom Nucleon – a proton or neutron Nucleus - the positively charged central core of an atom, consisting of protons and neutrons and containing nearly all its mass. Nuclide - An atomic nucleus identified by its atomic element and its mass number. Proton – a subatomic particle with a positive charge found in the nucleus of an atom Strong nuclear force - one of the four basic forces in nature, this force holds the nucleus together Subatomic particle - a particle smaller than an atom Paste into notebook Download A+ spelling Type the vocabulary term Enter the definitions Practice daily Until you know these terms you will be lost

Homework Online quizzes – Elements – both weeks – Read PT – Lab Equipment – Safety – Physical vs Chemical Vocabulary Worksheet on the number of subatomic particles.