atoms and elements Flashcards
What are elements
Elements are substances made up of only one kind of atoms.
What is a molecule?
A molecule is made up of elements of the same kind.
What are the physical properties of metals?
。physical state: solid at r.t. (except mercury)
。appearance: shiny
。strength: strong
。m.p & b.p.: high
。density: high
。thermal conductivity: good
。electrical conductivity: good
。malleability: malleable
。ductility: ductile
What are the physical properties of non-metals?
。physical state: solid or gases at r.t. (except bromine)
。appearance: dull (except diamond)
。strength: brittle
。m.p & b.p.: low
。density: low
。thermal conductivity: poor
。electrical conductivity: poor
What are semi-metals?
。boron, silicon
。have properties of both metals and non-metals
What is an atom made up of?
protons, neutrons, electrons
What is atomic number?
Atomic number is the number of protons
What is mass number?
Mass number is the sum of protons and neutrons
What is a cation?
A cation is a positive ion
What is an anion?
An anion is a negative ion
What is the formation of a cation and an anion?
Cation:
。loose electrons
Anion:
。gain electrons
