Chemical Bonding Revision Notes

Bartley Secondary School Science Department Name: ______________________ Date: _____________ Class: ______________ Revision notes on Chemical Bonding Atoms lose or gain electrons to achieve a stable octet structure. (8 valence electrons)  Metal atoms  give away electrons positive ions (cations)  Non-metals gain electrons  negative ions (anions). Ionic bonding • Occurs when a metal atom combines with a non-metal atom • Formed by TRANSFER OF ELECTRONS FROM A METAL ATOM TO A NON-METAL ATOM • Occurs between ions of opposite charges attracting each other Transfer of electrons Covalent bonding • Occurs mostly between non-metals • Formed by SHARING OF ELECTRONS between two atoms. Sharing of electrons Prepared by Miss Syikin, 2007.

Bartley Secondary School Science Department Differences between ionic and covalent compounds. Property Ionic compound Covalent compound Electrical conductivity Conducts electricity when Does not conduct molten or dissolved in electricity in any state water Melting and boiling High Low points Solubility in water Mostly soluble Mostly insoluble Solubility in organic Mostly insoluble Mostly soluble solvents List of common cations and anions Cations (positive ions) Anions (negative ions) Ammonium ion NH4+ Chloride ion Cl- Aluminium ion Al3+ Fluoride ion F- Calcium ion Ca2+ Bromide ion Br- Copper (I) ion Cu+ Iodide ion I- Copper (II) ion Cu2+ Nitrate NO32- Hydrogen ion H+ Sulphate SO42- Iron (II) ion Fe2+ Oxide O2- Iron (III) ion Fe3+ Hydroxide OH- Magnesium ion Mg2+ Sodium ion Na+ Potassium ion K+ Zinc ion Zn2+ Prepared by Miss Syikin, 2007.

Bartley Secondary School Science Department Name: ______________________ Date: _____________ Class: ______________ Revision Practice 1. The electronic structure of sodium and chloride atoms are respectively 2.8.1 and 2.8.7. (a) What is the valency of chlorine in sodium chloride? ……………………………………………………………………………………… (b) (i) Draw the electron arrangement of the particles formed when an atom of sodium reacts with an atom of chloride. (ii) What is the name given to this type or bonding? ……………………………………………………………………………………… (iii) How does this bonding help to explain the high melting point of sodium chloride? ……………………………………………………………………………………… ……………………………………………………………………………………… 2. The electronic configuration of a sulphur atom is 2.8.6. (a) Write in the same way, the electronic configuration of the atoms of carbon and oxygen. Carbon ……………………………….. oxygen …………………………… Prepared by Miss Syikin, 2007.

Bartley Secondary School Science Department (b) Draw a diagram showing the electronic arrangement in a molecule of carbon dioxide. 3. Three properties of five substances are shown in the table below. Each substance is represented by a letter. Substance Melting point /°C Electrical conductivity Solid liquid V 1083 Good Good W 870 Nil Good X -23 Nil Nil Y 2027 Nil Nil Z 98 Good Good State the letter of a substance which is: (a) a solid at 1100°C ……………… (b) ionically bonded ……………… (c) most likely to be soluble in water ……………… (d) composed of small, cavalently-bonded molecules ……………… 4. Complete the following table; Formula Type of bond (a) sodium chloride (b) carbon monoxide (c) water (d) methane (e) copper (II) oxide Prepared by Miss Syikin, 2007.

Chemical Bonding Revision Notes

by khirsyaban on Nov 12, 2009

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