C1 and C2- Atomic structure and the periodic table Flashcards
What did Aristotle do?
He proposed that there are 4 distinct substances (fire, water, earth,wind) that each had their own properties (e.g water is cold) and so made a chart or table to record these elements, the first proposal of the periodic table.
What did Antoine Lavoisier do?
Worked in the 1700s, he tested the theory that Aristotle proposed. He used a process called electrosis to separate these substances and proposed that if it can decompose or be physically separated then it is not an element. He used electrosis to separate water to oxygen and Hydrogen, and air into oxygen and nitrogen. This concluded that water and air were not elements, but hydrogen, nitrogen and oxygen were.
What did John newlands do?
He created the law of octaves, that properties repeat every 8th element. He was the first to arrange the elements into a periodic table with increasing order of atomic masses. He arranged elements into 8 groups but left no gaps for undiscovered ones.
What did Mendeleev do?
Working in the 1800s, he saw similar chemical properties in elements. He proposed that hydrogen, lithium and sodium had similar properties and so placed these into a structure that could catalogue these elements and similar properties . He left spaces for undiscovered properties and was able to predict further elements such as noble gases.
A row of elements is called?
A period
A column of elements is called a?
Group
If there is a metal in group 1, how many electrons does it have in its outer shell?
- The atoms of elements in the same group have the same number of electrons in their outer shell.
The atomic number shows the?
Amount of protons the atoms of that element has.
The atomic mass show the?
Amount of protons AND neutrons that atom has.
How can you tell which number is the atomic number and which one is the mass number?
The atomic number is always the smallest of the two.
The atoms of elements in the same period (rows) have the same number of…
Shells
What order are the elements arranged in?
Increasing atomic number. (No of protons)
When he was organizing the periodic table, what did Mendeleev discover?
That the elements displayed a pattern of chemical properties that repeated. He formed a new row on the table every time the pattern repeated.
What should you ignore when counting your groups?
The middle “transition metals” section
Why are elements arranged into groups?
If they have the same number of electrons in their outermost shells. (e.g group 5 will have 5 electrons in their outermost shell)
What are the differences between Mendeleevs periodic table vs the modern periodic table?
Look at photos for table of differences (if not then one of the differences is that Mendeleev grouped his elements into order of atomic mass however today it is grouped into order of atomic number.
