topic1-key concepts in chem Flashcards
(21 cards)
what is the electron shell rule
1st shell=2 electrons, 2nd shell=8electrons, 3rd shell=8electons
what are ions
charged particles
what happens when a shell gains an ion
becomes negative
what happens when a shell loses an ion
it becomes positive
which groups are most likely to form ions
group 1,2,6,7
what structure do ionic compounds have
regular lattice
ions form a closely packaged regular lattice which means
they are very strong electrostatic forces of attraction
ions have strong attraction which means
they have a high melting and boiling point
benefit of 2D representation of structures
simple and great at showing what atoms it contains
disadvantage of 2D representation of a structure
don’t show the shape
benefit of dot and cross diagram that show a structure
shows how compounds or molecules are formed
disadvantage of dot and cross diagram of a structure
don’t show size
benefit of 3D model of a structure
show arrangement of ions
disadvantage of 3D models that show a structure
only shows the outer layer of a substance
benefit of ball and stick models that show a structure
help visualise the structure and are more realistic
disadvantage of ball and stick models when showing a structure
don’t show correct scales
what are the properties of simple molecular substance
very strong covalent bond but forces of attraction are very weak
name properties of a giant covalent bond
very high melting and boiling point
describe the diamond structure
it’s a strong and takes lots of energy to break
describe the graphite structure
very weak because there aren’t any covalent bonds between layers
what’s a general property of metal
strong, lots of energy, high melting and boiling points
