Topic 1 Concepts in Chemistry - The Periodic Table Flashcards
How did Mendeleev arrange the elements in his periodic table?
Elements arranged with increasing atomic masses.
Elements with similar properties put into groups (due to periodic trends in chemical properties).
Switched the position of some elements.
Gaps left for undiscovered elements.
How was Mendeleev able to predict the properties of new elements?
Mendeleev left gaps in his periodic table.
He used the properties of elements next to these gaps to predict the properties of undiscovered elements.
Mendeleev’s table lacked some amount of accuracy in the way he’d ordered his elements. Why was this?
Isotopes were poorly understood at the time.
Protons and neutrons had not yet been discovered.
How are elements arranged in the modern periodic table?
In order of increasing atomic number.
Fill in the blank ‘Elements in the same group (column) have similar ______ ______’
Chemical properties
Why do elements in the same column have similar chemical properties?
Same number of outer shell electrons.
Number of outer shell electrons determines how an atom reacts.
What does the period (row) number tell you about all the elements in that period?
Elements in the same period have the same number of electron shells.
e.g. all elements in period 4 have 4 shells of electrons.
What does group (column) number tell you about all the elements in that group?
All elements in the same group have the same number of outer electrons.
e.g. all elements in group 2 have 2 electrons in their outer shell
On which side of the periodic table are the metals positioned?
Left hand side.
What determines whether an element is a metal or non-metal?
Atomic structures of the elements.
What is the maximum number of electrons allowed in each of the first 3 shells?
1st shell: 2
2nd shell: 8
3rd shell: 8
When are atoms most stable?
When they have full electron shells.
The atomic number of Na is 11. What is the electron configuration of Na?
2, 8, 1
How is the electron configuration of an element related to its position in the periodic table?
Diagram:
The number of rings is the period
The number of electrons in the outer ring is the group.
The total number of electrons is the atomic number.
Number (e.g. sodium 2, 8, 1)
Sodium has 3 shells as there are 3 numbers.
The last number is the number of outer shell electrons/the group.
The sum of the digits is the atomic number.
