Chem Unit 2 - Virginia

Atomic Number

The number of protons in the nucleus, which determines its place on the periodic table

Atomic Mass

The total number of protons and neutrons in a nucleus

Isotopes

Atoms of the same element that have different masses & different neutrons

Protons and electrons both:

Have an electrical charge

Protons

The subatomic particle that identifies an atom

Valence Electrons

Electrons on the outermost energy level of an atom

Subatomic particle that has no charge:

Neutron

Subatomic particle that has no mass

Electron

Atom

The smallest piece of an element that retains the properties of that element

Nucleus

A dense region in the center of an atom; it is made of protons and neutrons and contains almost all of an atom's mass

Electrons live

Outside of the nucleus

Most of the atom is made up of

Empty space

Atomic number is the__

Number of protons In nucleus of atom

Mass number is the__

Sum of protons and neutrons in an atom

In a neutral atom the__

Number of protons equals the number of electrons

Ions = ___

Charged atoms

Cation (+ Charge) ….

Lose electrons! (Subtract # of protons w/ atomic #)

Anion (-Charge)

Gain electrons! ( Add # of protons w/ atomic #)

Mass formula =

P⁺ + n_⁰

Chemical properties of isotopes of the same element are..

The same.. because chemical behavior is associated with electrons not neutrons

Physical properties of isotopes are..

Different because physical properties are based on mass

Atomic mass =

Weighted average of the masses of all naturally occurring isotopes of that element

Scientist: Dmitri Mendeleev..

Published a table with elements organized by increasing atomic mass

Period Table: Periods (There are 7!!)

The horizontal rows of the table are called (PERIODS OR ENERGY LEVELS)

Elements in the same period have…

The same number of shells/energy levels

Vertical columns of the periodic table are called..

Groups or families

Elements in any group of the periodic table have…

Similar physical and chemical properties

Elements in the same group have..

Same number of valence electrons

Electron configuration is..

Representation of the arrangement of electrons in the energy levels, sublevels, and orbitals

Abundance formula

(Mass * Abundance %/100) + (Mass * Abundance %/100)

How to calculate neutrons =

mass - atomic

John Dalton developed..

Atomic Theory - Solid Sphere Model

JJ Thomson discovered…

Electrons - Plum Pudding Model

Ernest Rutherford discovered…

Nucleus - Gold Foil Experiment

Niels Bohr discovered..

Electrons have a defined path - Bohr Model

how do you find if an isotope is more abundant than another?

by the ratio of the number of neutrons to the number of protons in the nucleus.

James Chadwick discovered…

Neutrons - Quantum mechanical model

Erwin Shrodinger discovered…

Electron cloud - Quantum mechanical model

Louis Debroglie discovered…

Particles can have wave like properties…

In the electron cloud, electrons are found & allowed in only certain__

energy levels, in the electron cloud

The electrons further from the nucleus are found in__

higher energy levels

What state are electrons normally found in?

Ground state

when the electrons in an atom becomes excited by absorbing energy from their surroundings, they jump to__

higher energy levels

the excited state is less__ than the ground state therefore__

LESS STABLE! and FALLS BACK or relaxes to return to the lower energy ground state

When electrons fall back a specific amount of__

quantum energy is emitted

Atomic emission Spectra - the energy is given out in the form of__

a photon of light

If we see color, then the emission is __

In the visible range

Energy is always ___

Increasing

Wavelength is always__

Increasing

The length of a wave is ____ related to its energy

Inversely

Violet light energy = __ energy, __ wavelength

HIGHER ENERGY, SHORTER WAVELENGTH

Red light energy = __ energy, __ wavelength

LOWER ENERGY, HIGHER WAVELENGTH

White light is made up of ___

ALL COLORS of the spectrum

Which region of the electromagnetic spectrum has the longest wavelength?

Radio

Which region of the electromagnetic spectrum has the shortest wavelength?

Gamma ray

For noble gas notation - How to find noble gas using electron configuration?

By the FAR RIGHT of the periodic table.