Electron Configuration and Atomic Properties

Section 11.4

PERIOD 6 Group #2

Background - Electron; covers a broad area it also behaves like cloud in an atom • to understand how the principal energy levels fill with electrons in atoms beyond hydrogen.

• to learn about valence electrons and core electrons.• to learn about the electron configurations of atoms with Z < 18.• to understand the general trend in properties in the periodic table.

Electron Configuration

• The electron arrangement in atoms from Z = 1 to Z = 18 can be described by placing electrons in principal energy level

• Principal energy level – energy denoted by principal quantum number n. ex. – n = 1 , n = 2, n = 3….

• The 1st element in the each period of the Periodic Table represents a new principal energy level.

• Ex. – hydrogen has lone electron in 1s orbital / so represents 1s^1 because it is in electron arrangement

• Electron arrangement – can be called electron configuration in an atom

https://teach.lanecc.edu/gaudias/scheme.gif

http://cwx.prenhall.com/bookbind/pubbooks/hillchem3/medialib/media_portfolio/text_images/CH08/FG08_06.JPG

Question #1

• For the first 18 elements, what is the sublevel order and the elements?

Answer #1

• 1s 2 s 2p 3s 3p are the sublevels for the first 18 elements.

Orbital Diagram• Also known as the box diagram• Gives more detailed information

about electron configuration• Arrows represent an electron

spinning in a particular direction.• For each element’s orbital – takes

one electron before any orbital in each sub level can receive another electron.

• Pauli Exclusion Principle –

Question #2

• What is the electron configuration and orbital diagram for silicon?

Example of Orbital DiagramAnswer #2

• Silicon – 1s^2 2s^2 2 ^6 3s^2 3p^2

Metal & Non-metal & Metalloids Chart

Metals Non-metals Metalloids

Gallium crystals from left to right He, Ne, Ar, Kr, Xe

Boron

Iron (Fe) from left to right; F, Cl, Br, l

Silicon

Copper(Cu) Sulfur Germanium

All URL on “Reference” page

Metals & Nonmetals & Metalloids• Metals and nonmetals have relatively large ionization

energies.• Metals gain electrons • Lower left region of the periodic table have the lowest

ionization energies (are the most chemically active metals)• Upper right region of the periodic table have the highest

ionization energies (are the most chemically active nonmetals)

• Metalloids – found along the stair-steps line between the metals and nonmetals.

• Metalloids have properties of both metals and nonmetals.

Question #3

• Name the physical properties of the metals.

Answer #3

• A lustrous appearance, the ability to change shape without breaking, and excellent conductivity of heat and electricity.

Atomic Size

http://www.avon-chemistry.com/p_table_atomic_rad.jpg

•Increases down a group

•Decreases to the right of the period.

•The average distance of the electrons from the nucleases increases.

•Atoms get bigger as electrons are added to larger principal energy levels.

•The sizes of atoms vary

•The atoms in a particular period all have their outermost electrons in a given principal level

Question #4

• Which element has the smallest atomic size?

Answer #4

The element with the smallest atomic size ishelium.

Ionization Energy

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Ionization Energy

• The energy required to remove an electron from and individual atom in the gas phase.

• Increases up a group and to the right of a period.

• Metals have relatively low ionization energies. • Ionization energies tend to decrease in going

from the top to the bottom of a group.

Question #5

• What is the definition of ionization energy and how does it related to the elements?

Answer #5

• It is the energy to remove an electron from an individual atom in the gases phase of an element and the energies tend to decrease going down a group.

Quiz1) What is the electron configuration for Cerium (Ce;

atomic #58)? Include a box diagram.

2) What is the Pauli Exclusion Principle and how does it relate to the orbital diagram?

3) Out of the metals and non-metals, which has relatively large ionization energy?

4) In which pattern so metals tend to lose electrons? Explain.

5) Define atomic mass and atomic size.

Answer key

1) 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2 4f^1

2) 2 electrons in the same level cannot be in the same quantum state so in the orbital diagram, the arrows cannot be in the same direction, and each orbital can only hold up to 2 electrons.

3) Nonmetals 4) Metals tent to lose electrons going down a group because as we go

down a group, the electron being removed resides on average farther and farther from the nucleus.

5) Atomic mass is the mass of an atom and atomic size is the size of the atom.

Reference• https://teach.lanecc.edu/gaudias/scheme.gif• http://www.avon-chemistry.com/p_table_atomic_rad.jpg• http://nanotech.sc.mahidol.ac.th/genchem/bonding1/ie.jpg• http://cwx.prenhall.com/bookbind/pubbooks/hillchem3/medialib/media_portfolio/

text_images/CH08/FG08_06.JPG• http://upload.wikimedia.org/wikipedia/commons/0/0c/Gallium1_640x480.jpg• http://upload.wikimedia.org/wikipedia/commons/0/03/Fe%2C26.jpg• http://upload.wikimedia.org/wikipedia/commons/a/a0/Burning-sulfur.png

http://upload.wikimedia.org/wikipedia/commons/d/d3/Edelgase_in_Entladungsroehren.jpg http://upload.wikimedia.org/wikipedia/commons/f/f5/Halogene.jpg

• http://upload.wikimedia.org/wikipedia/en/thumb/e/e9/SiliconCroda.jpg/800px-SiliconCroda.jpg

• http://upload.wikimedia.org/wikipedia/commons/5/5e/Germanium.jpg http://upload.wikimedia.org/wikipedia/commons/4/41/Schattenkreuzr%C3%B6hre-in_use-lateral_view-standing_cross.jpg