C4 - Chemical Patterns Flashcards
(52 cards)
What two properties are elements groups based on?
Relative atomic mass and properties
What did Johann Döbereiner do?
He noticed triads that linked patterns of the relative atomic masses of three elements
What did John Newlands do?
Noticed octaves where every eight element had similar properties
Why did scientists reject Döbereiner and Newlands’ ideas and accept Mendeleev’s?
The triads and octaves patterns didn’t work for all elements
New elements that were discovered fitted Mendeleev’s predictions
How was helium discovered?
Scientists looked at the light from the sun, split it using a prism and examined it’s line spectra noticing helium amongst it
What is the charge and mass for all three parts of an atom?
Proton, +1 charge, mass of 1
Neutron, 0 charge, mass of 1
Electron, -1 charge, mass of nearly 0
How can you work out the relative atomic mass of an element?
Proton number + neutron number = relative atomic mass
Give an example of how electron arrangements are used using Oxygen (8 electrons):
With dots e.g. 2.6
Number of electrons in an atom is _________ the proton number
Equal to
How many electrons are allowed in the first 4 shells and how can this information be found in the periodic table? (5)
In Shell 1=2, 2=8, 3=8, 4=18
Number of elements in a period = number of electrons allowed in that shell
The _____ an electron shell is to the nucleus, the _____ the energy level
Closer, lower
Period
A row in the periodic table
The _____ the proton number, the _____ the melting point and the _____ the boiling point
Higher, lower, higher
Describe the main properties of Elements in group 0 (2)
They have full outer shells and are Unreactive or inert gases
Link the number of outer shell electrons to an element’s likelihood to be metal or non metal:
Elements with up to 3 electrons in their outer shell are metals
Elements with 5 or more electrons in their outer shell are non metals
Group
A vertical column in the periodic table
Describe group 1 elements (3)
- Alkali metals
- Can be cut with a knife to reveal a shiny surface
- they tarnish quickly in moist air
How are group 1 elements stored? And why?
In oil, to prevent them from reacting with air or water
The _______ the group one element in the periodic table, the ______ reactive
Lower down = more reactive
What are the chemical hazards of group one metals and their products? (3)
They are flammable and their hydroxides are harmful and corrosive
What is the equation for the reaction of a group one element and water?
Metal + water -> metal hydroxide + hydrogen
The general balanced with state symbols equation for the reaction of group one elements is? (Using M to represent them)
2 M(s) + 2 H2O(l) -> H2(g) + 2 MOH (aq)
Where are the transition metals in the periodic table?
In the middle
Thermal disposition
Thermal disposition: when a substance breaks down into two or more substances
