Chemistry Unit 1 Kat 3 Flashcards
(45 cards)
Metallic Bonding:
Is the electrostatic attraction between metal cations and the sea of delocalised electrons around them. These delocalised electrons move freely, holding the structure together.
What are delocalised electrons:
They are electrons that are not attached to any particular atom. They are shared by all of the atoms and are free to move throughout the lattice.
Structure Metals:
Metals consist of close packed positive ions (cations) surrounded by a sea of delocalised valance electrons.
Metallic Crystals:
The lattice is a three-dimensional structure where metal cations are arranged in a regular pattern. The electrostatic attraction between the cations and delocalized electrons gives metals their unique properties.
Properties of Metals; Lustre (Definition)
Metals reflect light, giving them a shiny surface.
Properties of Metals; Lustre (Explanation)
The delocalised electrons reflect the light of any wavelength , producing a shiny and glossy surface.
Properties of Metals; Malleability (Definition)
Metals can be hammered or pressed into thin sheets without breaking.
Properties of Metals; Malleability (Explanation)
The layers of metal cations can slide over each other without breaking the metallic bond because the delocalized electrons adjust to new positions
Properties of Metals; Ductility (Definition)
Metals can be drawn into thin wires.
Properties of Metals; Ductility (Explanation)
Similar to malleability, the cations can shift positions while still being held together by the delocalized electrons.
Properties of Metals; High Melting and Boiling Points (Definition)
Most metals have high melting and boiling points.
Properties of Metals; High Melting and Boiling Points (Explanation)
The strong electrostatic forces between metal cations and the sea of electrons require a lot of energy to break.
Properties of Metals; High Thermal Conductivity (Definition)
Metals transfer heat efficiently.
Properties of Metals; High Electrical Conductivity (Definition)
Metals allow electricity to pass through them easily.
Properties of Metals; High Thermal Conductivity (Explanation)
Delocalised electrons allow metals to be good conductors of heat as when a piece of metal absorbs heat, the rise in heat will result in an increase in kinetic energy, which vibrates the cations and speeds up the delocalised electrons. The delocalised electrons carry the heat throughout the lattice.
Properties of Metals; High Electrical Conductivity (Explanation)
Free moving delocalised electrons will move towards a positive electrode in an electrical circuit all in one direction, thus conducting electricity.
Metal Reaction with Water
Metal+Water→Metalhydroxide+Hydrogengas. Some metals react with water which indicate they are very reactive.
Metal Reaction with Acid
Metal+Acid→(Metal) Salt+Hydrogengas (along with heat). This is an exothermic reaction. More metals readily react with acid than water.
Metal Reaction with Oxygen
Metal+Oxygen→Metaloxide.
Reactivity Series of Metals
A reactivity series ranks metals from most to least reactive based on their tendency to lose electrons (undergo oxidation).
More reactive metals lose electrons easily and form positive ions (cations) faster.
Less reactive metals resist oxidation and remain as solid elements longer.
Reactivity trend:
K > Na > Ca > Mg > Zn > Fe > Cu > Ag > Au.
What is an Ionic Compound
An ionic compound is a is formed between metals and nonmetals. Metal atoms donate their valance electrons to non-metal atoms to form cations and anions. Ionic compounds have no overall charge.
Common Properties of Ionic Compounds
Ionic compounds have distinct physical properties due to the strong electrostatic forces between oppositely charged ions in a three dimensional crystal lattice.
Ionic Compound properties: Hardness (Definition)
Hardness refers to how resistant a substance is to scratching or deformation.