C4 - Chemical Patterns Flashcards
What is a group?
A vertical column.
What is a period?
A horizontal row.
Alkali metals react with water to form what?
Metal hydroxide and hydrogen gas.
As you go further down The Halogens group, the reactivity ________, the melting/boiling points ________ and the density ________.
As you go further down The Halogens group, the reactivity decreases, the melting/boiling points increase and the density increases.
Describe displacement reactions of halogens.
They displace less reactive halogens from an aqueous solution of its salt.
Who invented the first Periodic Table, and what were the problems with it?
Newlands developed it, and elements were put into groups of 8, called octaves.
Problems
- No gaps.
- Things were a bit mixed up - there were metals and non-metals.
- Not everything was elements.
Who invented the new Periodic Table, what were the advantages with it and how has it changed since?
Mendeleev invented the new Periodic Table, however one change was made before it became the modern Periodic Table - the atomic number was used to order the elements. Note that this is NOT atomic mass. This solved problems such as Iodine having a lower relative atomix mass than Tellurium, so it should become before Tellurium according to his rules, however Iodine had similar properties to Fluorine, Chorline and Bromine, so he had to break his own rules.
Benefits
- Had gaps.
- Predicted properties of undiscovered elements.
- Groups where elements with similar properties were arranged vertically.
What group(s) can the alkali metals be found in?
Group 1.
What group(s) can the halogens be found in?
Group 7.
What group(s) can the transition metals be found in?
Between groups 2 and 3.
What group(s) can the transition metals be found in?
Groups 1-3 are metals.
Groups 3-6 are mixed.
Groups 7-0 are non-metals.
In the element below, what does the 12 represent?
The mass number.
(The number of neutrons and protons).
In the element below, what does the 6 represent?
The atomic number.
(The number of electrons and protons).
How do you find the number of neutrons?
Mass Number - Atomic number.
What is the standard reaction for:
Alkali metal + Water –> ___________?
Alkali metal + Water –> Metal Hydroxide (Salt) + H2.
Why do Group 1 metals get more reactive as you go down the group?
Because the negative electron wanting to leave has less force keeping them to the positive nucleus due to the further shell distance.
(Elements higher in the group have less shielding).
Why do Group 7 elements get less reactive as you go down the group?
Because there is less shells for elements at the top of the group for the positive force to attract negative electrons with, so it’s easier to attract the electron needed to fill the shell.
(Elements lower in the group have more shielding).
