C1: Periodic table Flashcards
How are elements in the periodic table arranged?
The elements in the periodic table are arranged in order of atomic
(proton) number and so that elements with similar properties are in columns, known as group
Why is the periodic table called the periodic table
The table is called a periodic table
because similar properties occur at regular intervals
Whats similar about elements in the same group?
Elements in the same group in the periodic table have the same
number of electrons in their outer shell (outer electrons) and this
gives them similar chemical properties.
How did John Newland order elements in the periodic table
John Newland ordered elements in order of increasing atomic mass
HE found that every 8th element reacts in a similar way and he called these NEwlands octaves
Before the discovery of protons, neutrons and electrons, scientists
attempted to classify the elements by arranging them in order of
their atomic weights.
What was the problem with ordering elements with increasing atomic number
When the periodic table was arranged not all elements had been discovered so it was not complete
Some elements were put in the wrong group with other elements that didn’t have the same properties
What was the problem with ordering elements with increasing atomic number
When the periodic table was arranged not all elements had been discovered so it was not complete
Some elements were put in the wrong group with other elements that didn’t have the same properties
How did Mendeleev solve New lands problem
Mendeleev discovered the 1st modern periodic table
He started of by ordering elements in increasing atomic mass
However Mendeleev solved Newlands problems by leaving gaps for elements that he thought were not discovered yet
And he predicted the properties of the undiscovered elements based on the elements in the same group
He also changed the order of some of the elements so they fitted the pattern of other elements in the same group
Elements with properties predicted by Mendeleev were discovered and filled the gaps.
Give an example of when Mendeleev changed the order of elements in the periodic table
And example of this can be seen with Tellurium(Te) and Iodine(I).
Iodine has a smaller atomic mass that Tellurium but it is placed after Tellurium as it has similar properties to elements in that group
Why is ordering elements in order of increasing atomic mass not correct
Knowledge of isotopes made it possible to explain why the order based on atomic weights was not always correct.
This is because isotopes of the same element have different atomic masses but the same chemical properties
What is the periodic table
The periodic table is a table that contains all the known elements(about 100)
How is the periodic table arranged
The table is laid out in order of increasing atomic number so that elements with similar properties form columns
The verticle columns are called groups and the horizontal columns are called periods
Why is the Periodic table useful
The periodic table is a useful way for working out which elements are metals and which are non-metals
Metals are on the left of the periodic table and non-metals are on the right
