Chemistry of LifeChemistry of Life

Chapter 2Chapter 2

Three Subatomic Three Subatomic Particles:Particles:

ChargeCharge LocationLocation

ProtonProton +1+1 NucleusNucleus

NeutronNeutron 00 NucleusNucleus

ElectronElectron -1-1 Electron Electron cloudcloud

Atomic NumberAtomic Number

The number of The number of protons in an protons in an atomatom

Unique for Unique for every elementevery element

Atoms are always Atoms are always electrically neutral. electrically neutral. This means that This means that protons always equal protons always equal the electron.the electron.Atomic Structure Overview | Cell Biology | BiochemistryAtomic Structure Overview | Cell Biology | Biochemistry

How many protons & How many protons & electrons are in the electrons are in the following atoms?following atoms?

SiliconSilicon

NitrogenNitrogen

ZincZinc

14 p & 14 e14 p & 14 e

7 p & 7 e7 p & 7 e

30 p & 30 e30 p & 30 e

Mass NumberMass Number

The number of The number of protons and protons and neutrons in the neutrons in the nucleusnucleus

Mass Number – Mass Number – Atomic Number Atomic Number = Neutrons= Neutrons

How Many Neutrons How Many Neutrons are in:are in:

PotassiumPotassium

ArgonArgon

TinTin

20 n20 n

22 n22 n

69 n69 n

Atomic StructureAtomic Structure

LithiumLithium

PhosphorusPhosphorus