Unit 1 Flashcards
1
Q
Dmitri Mendeleev
A
- 1869
- order of increasing relative atomic mass
- left gaps for undiscovered elements
2
Q
Modern periodic table
A
- order of atomic number
- rows are called periods
- groups show number of electrons in outer shell
3
Q
mass number
A
protons + neutrons
4
Q
atomic number
A
protons
5
Q
isotope
A
same number of protons but different number of neutrons
6
Q
ionic bonding
A
metal + non metal
7
Q
properties of ionic compounds
A
- high melting/boiling points as energy is needed to break bonds
- conducts electricity as solution so ions are free to move
- brittle as layers will shift and like charges repel
8
Q
ball and stick
A
+ see atom arrangement
- can’t see electrons
9
Q
ionic models
A
+ clear lattice structure
- doesn’t show electrons
10
Q
displayed formula
A
+ see the bonds
- doesn’t show electrons
11
Q
dot and cross
A
+ clearly see electrons
- implies electrons are different
12
Q
covalent bonding
A
pair of electrons are shared between non metals
13
Q
simple covalent compounds
A
- low melting/boiling points as weak intermolecular forces
- strong covalent bond as electrostatic forces between nuclei and electrons
- liquid/gas at room temperature
14
Q
giant covalent compounds
A
- high melting/boiling points
- strong covalent bonds
- dont conduct electricity
15
Q
diamond
A
- carbon atoms covalently bonded to 4 other atoms
- tetrahedral lattice
- used in cutting tools like drills
