Elements forming compounds with chemical bonds
Electron transfer and ionic bondsAtoms ha
ve no charge. A charged particle is called an ion. If an atom loses an electron, it becomes a positively charged (+) ion. An ion that is positively charged is known as a cation. If an atom gains an electron, it becomes a negatively charged (-) ion. An ion that is negatively is known as an anion. The negative and positive ions attract each other to form an ionic bond. Complete the gaps in the text below:_____ have no charge. A charged particle is called an ___. If an atom loses an ________, it becomes a positively charged (+) ion. An ion that is positively charged is known as a ______. If an atom gains an electron, it becomes a negatively charged (-) ion. An ___ that is negatively is known as an anion. The negative and positive ions attract each other to form an _____ bond.
The formation of sodium and chloride io
Draw atoms and ions for lithium, potassium, fluorine, magnesium, oxygen, sulfur and alumin
b Draw diagrams of ionic bonding in LiF, KF, LiCl, NaF, MgCl2, AlF3, MgO, MgS, Na2O and Al2O3.
Physical properties of giant ionic structuresIonic bonds form when metal and non-metal atoms join. A substance with ionic bonding has an ionic structure. Each ion is firmly held in place by strong ionic bonds so they have high melting and boiling points. If melted, charged ions become free to carry an electric current. The ions also become free if dissolved in water so solutions are also electrolytes. The solids are insulators because the ions are not free to move and cannot carry a current. Sodium chloride NaCl, and magnesium oxide MgO are good examples.
Task C1.10 Pick out the substances which are (a) ionic (b) have covalent bonds (c) have high melting points (d) conduct electricity when molten: sodium chloride, sulfur dioxide, magnesium oxide, iron fluoride, carbon dioxide, NaBr, H2O, NH3, Al2O3, KCl.
Covalent bonds and electron sharingNon-metal atoms join using covalent bonds. When a covalent bond is formed, atoms share their electrons. The atoms then have full shells. One covalent bond needs one shared electron from each atom. Each atom involved has to make enough covalent bonds to fill up its outer shell. Sharing electrons is called covalent bonding. Below is a diagram to show hydrogen gas (H2).
Dot and cross diagrams
Draw atoms of F, H, O, N and C.Draw a dot and cross diagram for fluorine F2, hydrogen fluoride HF, water H2O, ammonia NH3, methane CH4, oxygen O2, nitrogen N2, ethene C2H4
Physical properties of giant ionic structuresIonic bonds form when metal and non-metal atoms join. A substance with ionic bonding has an ionic structure. Each ion is firmly held in place by strong ionic bonds so they have high melting and boiling points. If melted, charged ions become free to carry an electric current. The ions also become free if dissolved in water so solutions are also electrolytes. The solids are insulators because the ions are not free to move and cannot carry a current. Sodium chloride NaCl, and magnesium oxide MgO are good examples.
Task C1.10 Pick out the substances which are (a) ionic (b) have covalent bonds (c) have high melting points (d) conduct electricity when molten: sodium chloride, sulfur dioxide, magnesium oxide, iron fluoride, carbon dioxide, NaBr, H2O, NH3, Al2O3, KCl.
Covalent bonds and electron sharingNon-metal atoms join using covalent bonds. When a covalent bond is formed, atoms share their electrons. The atoms then have full shells. One covalent bond needs one shared electron from each atom. Each atom involved has to make enough covalent bonds to fill up its outer shell. Sharing electrons is called covalent bonding. Below is a diagram to show hydrogen gas (H2).
Dot and cross diagrams
Draw atoms of F, H, O, N and C.Draw a dot and cross diagram for fluorine F2, hydrogen fluoride HF, water H2O, ammonia NH3, methane CH4, oxygen O2, nitrogen N2, ethene C2H4
Physical properties of simple molecular substances
Simple Molecular Substances have low melting and boiling points and most are gases or liquid
s at room temperature. This is because of weak forces between the molecules. Molecular substances do not conduct electricity, because there are no ions. E.g. water.Draw diagrams to show how the molecular structures for the following might look: fluorine F2, hydrogen fluoride HF, water H2O, ammonia NH3, methane CH4, oxygen O2, nitroge
s at room temperature. This is because of weak forces between the molecules. Molecular substances do not conduct electricity, because there are no ions. E.g. water.Draw diagrams to show how the molecular structures for the following might look: fluorine F2, hydrogen fluoride HF, water H2O, ammonia NH3, methane CH4, oxygen O2, nitroge
No comments:
Post a Comment