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| Questão | Responda |
| describe ionic bonding | occurs between metals and non metals. electrons are transferred from metal to no metal atoms. positive and negative ions are formed |
| describe how Na +Cl is attracted to each other. | - The sodium is positively charged because it has lost a electron. - The chloride is negatively charged because it has gained a electron. electrostatic forces hold the compounds together. |
| describe how electrostatic forces form a latice | ionic compounds always create a latices as the attraction of the electrostatic bond is spread thought the compound so every positive ion attracts every negative ion |
| properties of ionic compounds | Solids at room temperature. Giant structures so high melting points because energy must be suplied to break up lattice. conduct electricity when molten or dissolved but not solid as ions are not free to move. brittle and shatter easily as of alternating pos and neg lattice. movement may cause interaction with same charge particles |
| what is a covalent bond | forms between non metal atoms. atoms share outer electrons so that each have a full outer shell. shared pair of electrons. |
| how does sharing electrons hold atoms together | held together by electrostatic forces of attraction between nuclei and and shared electrons. attraction forces and repulsion balance. |
| describe a double bond eg O=O | in a double bond 4 electrons are shared . The 2 atoms in a oxygen molecule share two pairs of electrons creating a double bond. |
| properties of molecular structres. eg. H20, CO2 | low melting points as strong covalent bonds only form between the atoms withing the molecule. poor conductors as they are neutral so there are no charged particles to carry current. dissolve in water and remain as molecules, does not conduct, no charged particles |
| describe a dative or co-ordinate bond | bond formed by sharing electron pair but the shared pair is contributed by one atom. |
| describe and draw a metallic bond | metals consist of a lattice of positive ions exsisting in a 'sea' of delocalised electrons |
| outline the properties of metals | -GOOD conductors of heat and electricity, delocised electrons are free to move -STRENGTH, depends on charge, more electrons to donate to sea so stronger the electrostatic attraction. size of ion closer closer electrons are to + nulclues, stronger bonds. Malleable and Ductile- after small distortion each metal ion is in same enviroment so not changed. High melting points- giant strucutres, strong attraction between metal ions and sea makes it hard to seperate. |
| what is electronegativity | The power of an atom to attract the electron density in a covalent bond towards itself |
| what does electronegativity depend on | 1)nuclear charge 2)distance between nucleus and outer shell 3)shielding of nuclear charge by inner shells. the smaller the atom the closer the nucleus is the the shared outer main level electrons( greater electronegativity) larger the nuclear charge, greater the electronegativity. |
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