C2 - The Periodic Table Flashcards
What is the Periodic Table of Elements?
The Periodic Table of Elements is a table where elements are arranged based on chemical properties.
What are the vertical columns in the periodic table called?
Groups
What are the horizontal rows in the periodic table called?
Periods - each period has the same number of shells. The further periods you go, the bigger the size of the positive nuclear charge.
E.g:
- period 1 = 1 shell (2)
- period 2 = 2 shells (2.8)
- period 3 = 3 shells (2.8.8)
Who are the 3 scientists that were involved in the development of the Periodic Table? What was each of their developments?
John Dalton (also linked to History of the Atom) - arranged elements into order of their atomic weights
John Newlands - produced law of octaves (properties of every eighth element seemed similar) - he left no room for new elements
Dmitri Mendeleev - solved the problem around atomic number by leaving gaps for new elements (and predicting their new properties based on the elements next to the gap) - he produced the periodic table we know today.
What determines an elements position in the Periodic Table?
Its atomic (proton) number - its chemical properties (electronic arrangement).
What determines an elements reactivity?
The number of electrons in the outermost shell (group number) - electronic structure.
What happens to metals when they react ionically?
Lose electrons - form positive ions
Metals found on LHS of table.
What is Group 1 called? What are some basic properties?
The Alkali Metals
Properties:
- Soft - low density
- Silvery and shiny surface (until react with oxygen).
- React with oxygen very well (become dull) - need to be stored in oil to stop oxidation.
- Relatively low melting points and boiling points compared to other metals.
Why are the alkali metals the most reactive metals?
Only have 1 outer electron.
Therefore it only needs to lose that 1 electron to become electronically stable.
What is the trend for reactivity in Group 1? Why? Does the size of the nuclear charge overpower the far distance and greater shielding effect?
Reactivity increases from top to bottom.
Lithium = Least Reactive Francium = Most Reactive
- Larger atoms (more shells each period).
- Nuclear attraction - the larger the atom, the further away the outermost shell is from the nucleus - outer electron can more easily leave.
- Inner shells screen/shield outer electrons from the nucleus’ positive charge.
No. The increasingly bigger positive nuclear charge going further down group, is massively outweighed by the greater distance and shielding effect.
What is the trend for melting point and boiling point in Group 1? Why?
Melting point and boiling point decrease from top to bottom.
Lithium = High BP/MP Francium = Low BP/MP
The electrons further up the group (e.g lithium) are closer to the nucleus and need more energy to break down.
How do the G1 elements Lithium (Li), Sodium (Na) and Potassium (K) react with water?
Lithium - Fizzes on surface of water.
Sodium - Fizzes violently and becomes a molten ball of sodium with a golden yellow flame.
Potassium - It burns with a lilac colour.
What is Group 7 called? What are some basic properties?
The Halogens
Properties:
- Low melting points and boiling points
- Poor conductors
- Exist diatomicly (F2, Cl2 etc…)
Why are the Halogens the most reactive non-metals?
Contains 7 electrons in the outer shell.
Therefore only needs to to gain 1 electron to become electronically stable.
What is the trend of reactivity in Group 7? Why? Does the size of the nuclear charge overpower the close distance and reduced shielding effect?
Reactivity decreases from top to bottom.
Fluorine = Most Reactive Astatine = Least Reacitve.
- The smaller the atom, the stronger the electrostatic acctraction from the nuclued.
- The less shells, the closer the distance between the outer shell and the nucleus.
- An electron can more easily join an atom with less shells.
- The less shells, the more the shielding effect from inner shells is reduced.
The closeness of the outershell to the nucleus, outweighs the smaller positive charge (less protons) as an electron recieves a greater electrostatic attraction.
