Periodic Table Flashcards
What was John Daltons periodic table?
It was arranged in order of atomic mass and gave the elements a unique symbol.
What was John Newlands periodic table?
It was arranged in order of atomic mass, it was placed in vertical groups that had similar properties.
What was wrong with John Newlands periodic table?
- Did not account for undiscovered elements, therefore when an element was found, the order had to break down.
- Some metals were placed in Non-Metals despite having different properties to each other.
What was Mendeleev’s Periodic table?
Arranged in vertical groups with elements that had similar properties, placed elements in order of atomic mass but not always. Left gaps for undiscovered elements.
What is the modern periodic table?
Arranged in order of atomic number, elements are in vertical groups with other elements with similar properties, The group number corresponds to the number of electrons in the outer shell. Metals and Non-metals are divided.
What is Group 1?
Group one consists of metals called ‘Alkali metals’, they all have one outer shell.
What are the key properties of the Alkali metals?
- very reactive
- float on water (low density)
- soft enough to cut with knife
- low melting point
- When reacting, they lose electrons to form 1+ ions.
What happens when an Alkaline metal reacts with water?
The metals will float on the surface and fizz as they produce hydrogen gas.
What is the reactivity like as you do down group 1?
As you go down the group, the outer electron is further away from the nucleus, causing less electrostatic attraction meaning it is easier to lose. therefore reactivity increases.
What is the melting point like as you go down group 1?
The melting point decreases due to the metallic bong strength getting weaker.
What is Group 0?
Group 0 are called the ‘Noble Gases’, they consist of having a full outer shell of electrons (unreactive) and exist as a single atom. They are gases at room temperature.
What is the boiling point like as you go down in group 0?
The boiling point increases, proportional to the atomic mass.
What is Group 7?
Group 7, are called Halogens, they all have seven electrons in their outer shell.
What are the key properties of the Halogens?
- weak intermolecular forces between the simple molecules
- they are bad conductors of heat and electricity.
- They form coloured vapours.
- When reacting, they gain electrons to form 1- halide ion.
How are halogens presented in their elemental form?
They exist as diatomic molecules, two atoms, this is because they covalently bond with themselves to achieve full outer shells.
