Science- atomic structure + the periodic table Flashcards
Atoms
The smallest unit of matter
Elements
Substances made of only one type of atom
Compounds
Substances made of 2/+ different elements chemically bonded
mixtures
Substances made of 2/+ different elements or compounds not chemically bonded
Isotope
atoms of an element with different amounts of neutrons
Protons (Charge, mass )
+1, mass of 1
Neutrons (Charge, mass )
0, mass of 1
electrons (Charge, mass )
-1 , 1/2000
Groups
elements with similar properties , arranged in verticle columns
How are the elements in the periodic table arranged?
Atomic number
Ions
A charged atom
Metals (where it is found, group + forms)
G1,2,3 , forms positive ions
None metals (where it is found, groups +forms
G 4,5,6,7,8/0 , forms negative ions
Halogens
group 7, the reactivity decreases down the group
Noble gases
group 0/8 ,unreactive
Reactivity
the tendency for a substance to have a chemical reaction
Pure subtance
substance made of only 1 type of element or compounds
formulation
designed with a specific useful purpose , made by mixing components in specific amounts
Examples of formulations
paint, medicine
melting point
temperature which a substance turns from solid -> liquid
does an impure or pure substance have a specific melting/boiling points?
pure
Positive ion
Formed when metal atoms lose electrons
negative ions
formed when metal atoms gain electrons
ionic bonding
electrostatic attraction between positive and negative ions
What does ionic bonding happen between?
A metal and non-metal
What ions does group 1 form?
1+
What ion does group 2 form?
2+
what ions does group 6 form?
2-
What ions does group 7 form?
1-
what do drawings of ions need
square brackets around the ion
What are the melting + boiling points of ionic compounds and why ( include how much energy needed to overcome)?
High because they have strong electrostatic forces of attraction - requires lots of energy to overcome
covalent bonding
sharing a pair of electrons between atoms to gain a full outer shell
what does covalent bonding happen in
non-metals
What are the 2 giant covalent structures
Diamond and graphite
How many carbon atoms is each carbon atom bonded to in diamonds?
4
do diamonds conduct electricty and why
no, no free electrons
How many carbon atoms is each carbon atom bonded to in graphite?
3
does graphite conduct electrity and why?
yes, delocalised electrons that are able to move between layers
Is it easy to break diamond ( in terms of energy) and melting point?
requires a lot of energy and has high melting point
What can graphite be used as, forces between layers (sliding)?
lubricant, layers of carbon can slider over each other easily , weak forces between layers