metals Flashcards
what type of surfaces do metals have?
shiny surfaces
why do metals have high melting points and boiling points?
large amount of energy required to overcome the strong electrostatic forces of attraction between the positive ions and sea of delocalised electrons
why are metals good conductors of electricity?
delocalised electrons can move freely to act as mobile charge carriers to conduct electricity
why are metals good conductors of heat?
delocalised electrons can move freely to transfer heat from one point to another quickly as the electrons gain energy and move faster
why are metals malleable/ductile?
pure metals tend to be soft as they are arranged in orderly manner which can slide across each other easily
why do metals have high density?
atoms are closely packed together in a given volume
what is an alloy?
a mixture of a metal with one or a few other elements
why are alloys stronger and harder than the constituent pure metal?
pure metal consists of atoms of the same size which are arranged in an oderly manner. when a force is applied, the layers of atoms can slide across each other easily, in an alloy, the different size of atoms from other elements disrupts the orderly arrangement of atoms, preventing the layers of atoms from sliuding over each other easily.
what is the metal reactivity series?
potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, (hydrogen), copper, silver, gold
what do reactive metals do?
lose electrons to form positive ions + react vigorously to form compound + have vigorrous effervesence in chemical reactions + corrode easdily when exposed to moist air/oxygen
why are reactive metals good reducing agents?
since reactive metals tend to lose electrons, it tends to oxidise itself
how do more reactive metals react with water?
metal + water -> metal hydroxide + hydrogen
how do less reactive metals react with steam?
metal + steam -> metal oxide + hydrogen
how does potassium react with cold water?
it reacts very vigorously with cold water, lilac flame observed, enough heat is produced to cause hydrogen gas to ignite and explode
how does sodium react with cold water?
react vigorously with cold water, hydrogen gas may ignite and catch fire, yellow flame observed
how does calcium react with cold water?
reacts quickly/readily with cold water
how does magnesium react with cold water?
reacts very slowly with cold water
how does aluminium/zinc/iron/lead/copper/silver/gold react with cold water?
no visible change
how does potassium/sodium/calcium react with steam?
reacts violently and explosively with steam
how does magnesium react with steam?
hot magnesium reacts vigorously with steam to produce a bright white glow, white solid formed
how does zinc react with steam?
hot zinc reacts readily with steam, yellow solid formed which turns white when cooled
how does iron react with steam?
hot iron reacts slowly with steam to form a black solid,
how does lead/copper/silver/gold react with steam?
no visible change with steam
how does potassium/sodium react with acid?
react violently and explosively with acid, effervesecne of colourless gas
how does calciumj react with acid?
reacts vigorously with acid, effervesence of colourless gas observed
how does magnesium react with acid?
reacts rapidly with acid, effersvesence of colourless gas