Electrons in Atom

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The atomic model presented in this textbook has considered atoms as consissting o protons and neutrons aking up a nucleus surrounded by electrons.

Ruthefords model explained only a few simple properties of atoms. It couldnt explain the chemical properties of elements.

What makes the electron configuration stable

-Energy and stability play an important role in determing how electrons are cofigured in an atom.

Three rules for writing an electron configuration of elements

Electron configuration is the arranagment of the electrons in various orbitals around the nucleus.

The Aufbau principle

he Pauli exclusion

Hunds rule

Aufau Principle

Electrons occupy the orbitals of lowest energy first.

Pauli Exclusion Principle

An atomic orbital may describe at most two electrons.

To occupy the same orbital, two electrons must have opposite spins, hat is, the electron spins must be paired.

Spin is a quantum mechanical property of electrond may be thought f as clockwise.

Hund's Rule

Electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spindirection as large as possible.

Steps Drawing a Lewis Structure

1.) The first step is count all valance electrons}

Lewis scture of N2

N2=5x2=10 v.e

N has 5 valance electrons