Electron ArrangementReview

Unit 3

NC Essential StandardsChm.1.1.2 • Analyze diagrams related to the Bohr model of the hydrogen atom in terms of allowed, discrete energy levels in the emission spectrum. • Describe the electron cloud of the atom in terms of a probability model. • Relate the electron configurations of atoms to the Bohr and electron cloud models.  Chm.1.1.3 • Understand that energy exists in discrete units called quantaDescribe the concept of ground and excited states of electrons in an atom1. When an electron gains an amount of energy equivalent to the energy difference, it moves from its ground state to a higher energy level. 2. When the electron moves to a lower energy level, it releases an amount of energy equal to the energy difference in these levels as electromagnetic radiation (emissions spectrum). • Articulate that this electromagnetic radiation is given off as photons. • Understand the inverse relationship between wavelength and frequency, and the direct relationship between energy and frequency. • Use the “Bohr Model for Hydrogen Atom” and “Electromagnetic Spectrum” diagrams from the Reference Tables to relate color, frequency, and wavelength of the light emitted to the energy of the photon. • Explain that Niels Bohr produced a model of the hydrogen atom based on experimental observations. This model indicated that: 1. an electron circles the nucleus only in fixed energy ranges called orbits; 2. an electron can neither gain or lose energy inside this orbit, but could move up or down to another orbit; 3. that the lowest energy orbit is closest to the nucleus. • Describe the wave/particle duality of electrons.

Essential Standard 1.3.2

Agenda: 3/3• Objective: To link the electron arrangements

concepts for atoms and ions• Warm-up: 3 methods to represent electron

arrangement• Review:

– Bohr model– Electromagnetic spectrum – 3 methods to write electron arrangement– Valence electrons and electron dot notation– Ions: forming ions and symbols

Homework: Study for test on WednesdayElectron arrangement, Bohr, Unit 1 & Unit 2

Warm-up:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹º4p⁵

1. What elements are represented? 2. What is the name of this electron arrangement? 3. Represent the element in two other ways:

Energy is related to the Electron’s orbits

• When an atom is:

• The electron will:– Start at the – Jump to – Number of jumps is related to

• Key researchers: Bohr, Plank, EinsteinSchrodinger

Overview

Describe the relationship between wavelength, frequency, and energy. If you have low energy, describe the wavelength and frequency.If you have high energy, describe the wavelength and frequency.

Electron Cloud Model

• Quantum Mechanical Model– Based on determining the probable location

of the electron

– Within the boundary of theatom, its electrons can be found 90% of the time(based on probability)

The electrons travel around the nucleus at high speeds and in complicated patterns.

Methods for Writing Electron Arrangements

• Orbital notation

• Electron configuration

• Noble gas notation

How are you going to remember the names for each method of writing the electron arrangement?

Check your warm-up answers1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹º4p⁵

1. What elements are represented? 2. What is the name of this electron arrangement? 3. Represent the element in two other ways:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹º4p⁵

Rules for Electron Arrangement• Aufbau:• Place the electron at the lowest energy orbital

possible. * • Pauli’s exclusion principle: Place a maximum of

2 electrons in each orbital.

• Hund’s rule: Place an electron in each orbital of a sublevel before pairing up.

* Check the diagram for the order of increasing energy level

Principal Energy Level Location of theValence electrons

Electron Configuration

• Principal energy level + sublevel • Use superscripts to show number of

electrons in each sublevel

1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

Orbital Notation • The orbital is indicated by a line____ wioth the

name written below. • Arrows represent the electrons.• ExamplesNe: ___ ___ ___ ___ ___ 1s 2s 2p 2p 2p

___ ___ ___ ___ ___ ___ ___ ___ ___ ___

Note: You must write both the lines and the orbital designations under the lines

Noble Gas Notation • Short cut method for electron arrangement• Use the noble gas in the period above the

element

• Example:Na 1s² 2s² 2p⁶ 3s¹- Use Neon - Represent neon’s configuration 1s² 2s² 2p⁶as [Ne]- Use in Na: [Ne] 3s¹

Arrow Diagram Remembering the order to place the electrons

1s

1s

1s 2s

1s 2s

1s 2s 2p

1s 2s 2p

1s 2s 2p

1s 2s 2p

1s 2s 2p

ElementAtomic #

andGroup #

Orbital diagram Electron Configuration Noble gas notation Valence e-Electron

dot

Ne

Ar

Mg

Ca

N

P

0

S

F

Cl

Br

Check your electron configuration answers using the Periodic Table

Periods

S, P, D, F Blocks

18

Electron Dot Notation – Maximun number = 8

Write the Electron Dot in the correct location for the element

1s

1s

1s 2s

1s 2s

1s 2s 2p

1s 2s 2p

1s 2s 2p

1s 2s 2p

Element

M?NM?

Electron Configuration

Atom

Electron ConfigurationIon

Symbol for Ion

Ne

Ar

Mg

Ca

N

P

0

S

F

Cl

Br

Forming Ions