C2 Flashcards
1
Q
Periodic Table
A
- chemists tried to classify the elements and arrange them in order
- regularly repeating patterns in the properties of elements
2
Q
Mendeleev’s periodic table
A
- left gaps for the unknown elements
- when discovered matched his predictions
- table was accepted by the scientific community
3
Q
electronic structure
A
- chemical elements are placed in order of their atomic number
- The number of electrons in the outermost shell determine its chemical properties
- Group number in periodic table equals the number of electrons in outer shell
4
Q
metal and non metal atoms
A
- atoms of metals tend to lose electrons
- atoms of non metals tend to gain electrons
5
Q
Group 0
A
- Noble gases in group 0 are unreactive because of their stable electron arrangements
6
Q
Group 1
A
- alkali metals
- melting and boiling points decrease down the group
- metals all react with water to produce hydrogen and alkaline solution containing metal hydroxide
- form +1 ions in reactions to make ionic compounds
- reactivity increases down the group
7
Q
Group 7
A
- halogens all form ions with single negative charges in ionic compounds with metals
- halogens form covalent compounds by sharing electrons with other non metals
- more reactive halogen can displace less reactive halogen from a solution of one of its salts
- reactivity decreases down group
8
Q
Explaining trends
A
-larger atoms lose electrons easily down a group
9
Q
The transition elements
A
- transition metals have higher melting points, densities, stronger, harder and less reactive than alkali metals
- do not react vigorously with oxygen and water
- important industrial catalysts
