2010-01-20 Chapter 02 Atomic Structure and Bonding

2010-01-20 Chapter 02 Atomic Structure and Bonding - ISSUES...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ISSUES TO ADDRESS... • What promotes atomic bonding? • What types of bonds are there? • What properties are inferred from bonding? 1 CHAPTER 2: Atomic Structure & Interatomic Bonding Why study Atomic Structure & Interatomic Bonding? Type of bond allows us to explain a material’s properties. e.g. Metallic bonded materials are good conductors of heat and electricity due to free electrons. Ionically and covalently bonded materials are typically insulative to heat and electricity e.g.ceramics. BACKGROUND • An Atom is the basic unit of matter. • Atom has a Nucleus composed of Protons (positively charged, +) & Neutrons (neutral). • Mass proton = Mass neutron = 1.67 x 10-27 kg • Number of protons = Z = Atomic Number, determines the chemical element • Number of Neutrons = N, determines the isotope • Sum of masses of protons and neutrons = A = Atomic Mass • Atomic Weight = Weighted Average of Atomic Masses, in g/mol • The Nucleus of an Atom is encircled by moving Electrons (negatively charged, -) • Mass = 9.11 x 10-31 kg <<< protons and neutrons. • Charge magnitude for an electron = -1.60 x 10-19 C • Charge magnitude for a proton = +1.60 x 10-19 C • Electrons strongly influence the magnetic properties of atoms. • Number of electrons = Number of protons for electrically neutral or, complete atom. • 1 mole of matter = 6.023 x 10 23 atoms or molecules = Avogadro’s number Chapter 2- Nucleus: Z = number of protons 2 orbital electrons: n = principal quantum number n=3 2 1 N = number of neutrons Adapted from Fig. 2.1, Callister 6e. BOHR ATOMIC MODEL In this model, electrons are assumed as particles revolving around nucleus in discrete orbitals. • Wave-mechanical model considers electron to exhibit both wave- like and particle-like characteristics. Position of electron is described by probability distribution • Electron in atom is characterized by Quantum Numbers . – Shells: principal quantum no.(n = 1,2,3,4,.. or, K, L, M, N) – Subshells: second quantum no.(s, p, d, and f) – Energy states: third quantum no. – Spin moment: fourth quantum no. WAVE-MECHANICAL ATOMIC MODEL Principal Quantum No Shell Subshell No. of Energy State No of Electrons Per Subshell Per Shell 1 K s 1 2 2 2 L s 1 2 8 p 3 6 3 M s 1 2 18 p 3 6 d 5 10 4 N s 1 2 32 p 3 6 d 5 10 f 7 14 Shells s,p,d,f are subshells ELECTRON ENERGY STATES 1. For smaller quantum number energy is lower. 1s < 2s < 3s 2. Within each shell energies are: s < p < d < f 3. There may be overlap in energies in the adjacent shells. e.g. 3d > 4s Electrons tend to occupy lowest available energy state. Important Chapter 2- • have discrete energy states or, levels. • tend to occupy lowest available energy state....
View Full Document

This note was uploaded on 09/30/2011 for the course PHYSICS 1410 taught by Professor Falco during the Spring '08 term at Texas State.

Page1 / 29

2010-01-20 Chapter 02 Atomic Structure and Bonding - ISSUES...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online