Revision YEAR 11 ATOMIC STRUCTURE

 What is the atomic number of an element?  What is contained in the nucleus?  What does the word valence mean?  What is the rule for filling the electron shells  What is the electron configuration of:  Sodium  Oxygen  Chlorine  Carbon GRAB A WHITEBOARD

 Draw me a diagram of a Nitrogen atom showing the electrons in their shells  Draw me the diagram of an oxygen atom  Now draw the diagram of the O 2- anion  Now draw the Sodium atom  Now draw the Na + cation ELECTRON DIAGRAMS

 Describe a metal  Describe a plastic  Describe an isotope SOLIDS

A/S – 2.4 TYPES OF BONDING

 What causes atoms of different atoms to react?  Why does your ice float in a glass of coke?  Why? BONDING IN CHEMISTRY

 Chemical reactions occur to substances to become more stable  The formation of a bond usually results in a more stable product.  For this reason atoms with incomplete outer (valence) shells will gain, lose or share electrons to allow them to become more stable STABILITY

 Natural substances are not single atoms  Chemical bonds are an electrostatic attractions  Two broad ways in which this attraction forms  Sharing of electrons  Transfer of electrons CHEMICAL BONDING

This year you will investigate and learn to describe three main types of bonding 1.Ionic Bonding 2.Covalent Bonding 3.Metallic Bonding TYPES OF BONDS

 This form of bonding occurs between a metal cation and a non-metal anion  The particles involved are ions – an atom or group of atoms that has a net positive or negative charge  These should be familiar from 2.2 ion identification IONIC BONDING

Ions are formed when an atom gains or loses electrons Metal atoms – generally form cations by losing electrons to form a positively charge species Non-Metal Atoms – form anions by gaining electrons to form a negatively charged species FORMING IONS

TABLE SALT – SODIUM CHLORIDE Na + Cl -

An ionic bond is: The bond formed between an atom that has lost electrons and an atom that has gained electrons. The strong electrostatic attraction is due to the presence of a positively charged cation and a negatively charged anion DEFINING AN IONIC BOND

 Ionic and covalent animation – click picture IONIC vs. COVALENT BONDING

 Electrons in this bond are shared  These electrons are termed ‘bonding electrons’  They simultaneously belong to each atom in the bond  Usually form between non-metal atoms COVALENT BONDING

 A chemical bond formed by the sharing of one or more electrons, especially pairs of electrons, between atoms. DEFINING A COVALENT BOND

 Chemical bonding will influence the physical properties of matter  Physical properties depend on:  Type of particle present – Atom, ions, molecules  Forces of attraction between particles  The force of attraction is determined by the chemical bonding EFFECTS OF BONDING