The Periodic Table Flashcards
What was the first attempt at making a periodic table?
Newlands’s Law of Octaves, 1864
How did Newlands present the elements?
In order of atomic mass in rows of seven. He said that each eighth element had similar properties so they were put in columns and became known as Octaves.
Why was Newlands’s Law of Octaves criticised?
- Some of his octaves contained elements that didn’t have similar properties
- He mixed up metals and non-metals
- He didn’t leave any gaps for undiscovered elements so new elements didn’t fit
How is Mendeleev’s periodic table similar to Newlands’s?
They both arrange the elements in order of atomic mass.
How many elements were there in Mendeleev’s original periodic table?
60
How was Mendeleev’s periodic table different to Newlands’s?
Mendeleev left gaps where the groups didn’t work and predicted the properties of those undiscovered elements.
What was proof that Mendeleev’s periodic table was a success?
When new elements were discovered they fitted into the gaps Mendeleev left.
How are elements arranged in the modern periodic table?
By atomic number.
What does group number on the periodic table tell us?
How many electrons an atom of that elements has on its outermost energy level.
What does period number on the periodic table tell us?
The amount of energy levels an atom of that element has.
What is shielding?
When lots of inner electrons get in the way of the nuclear charge between the nucleus and electrons.
What effect does shielding have?
The more shielding there is (the more full energy shells an atom has), the easier it is for an atom to lose its outermost electrons as it feels a weaker attraction to the nucleus. It also makes it harder for atoms to gain electrons as the attraction of the nucleus is weaker.
What is group one on the periodic table also known as?
The alkali metals.
What is the trend with reactivity in the alkali metals?
Reactivity goes up the further down the group you go.
What is the trend of melting points and boiling points in the alkali metals?
They decrease down the group.
What do the alkali metals react with non-metals to form?
Ionic compounds. The alkali metal will become a 1+ ion.
What are the products of alkali metals reacting with non-metals usually like?
White solids that dissolve in water to form colourless solutions.
What is the equation for an alkali metal’s reaction with water?
Alkali metal + Water -> Metal Hydroxide + Hydrogen
Describe how alkali metals react with water.
Vigorously - so much so that the elements below Potassium are explosive.
Why are the alkali metals named as such?
Because when they react with water the hydroxides made will dissolve in the water to make alkaline solutions.
What name is given to the group seven elements?
The halogens
What is Fluorine like at room temperature?
A poisonous yellow gas.
What is chlorine like at room temperature?
A poisonous dense green gas.
What is bromine like at room temperature?
A dense, poisonous, red-brown volatile liquid.
What is iodine like at room temperature?
A dark grey crystalline solid or a purple vapour.
True or False: Halogens are diatomic.
True
What is the trend of reactivity in the halogens?
Reactivity decreases down the group.
What is the trend of melting and boiling points in the halogens?
They increase down the group.
What is formed when a halogen reacts with a metal?
An ionic compound. A halogen becomes a 1- ion.
What is displacement?
The ability for a more reactive halogen to remove a less reactive halogen from an aqueous of its salt.
Where are the transition metals on the periodic table?
The middle.
What are two typical properties of transition metals?
- Very conductive
* Dense, strong and shiny
What are three differences between the transition metals and the alkali metals?
- Transition metals are a lot less reactive than alkali metals
- Transition metals are denser, stronger and harder than alkali metals
- Transition metals have much higher melting and boiling points than alkali metals.
What are two facts about ions of transition metals?
- Most can make ions of different charges
* Most form different coloured compounds
What is a use of the transition metals in industry?
Catalysts
