Chapter 2 - The Periodic Table Flashcards
How did John Dalton organize the elements which had been discovered?
He put them in a table in order of their atomic weight.
How did John Newlands build on Dalton’s idea?
He had presented the “Law of Octaves”. He arranged known elements in order of mass, with the 8th element having similar properties.
How did Mendeleev organize and build the modern periodic table?
He placed elements in order of atomic weight, in a periodic pattern to identify properties.
He left gaps to predict properties of undiscovered elements, with most of his prediction seeming accurate,
Why is Helium (He) and Argon (Ar) unreactive?
Their outer shells are already filled with electrons, meaning they are already stable.
Describe the reactivity and structure of the alkaline metals.
- React vigorously with water.
- One electron in their outer shell.
- Mostly very soft metals.
Describe the reactivity and structure of the transition elements.
- Quite unreactive.
- Mostly quite hard and malleable.
As you go down the group of the alkali metals……….
The reactivity increases and their melting and boiling points decrease.
What products are produced when an alkali metal reacts with water?
- Hydrogen
- An alkaline solution containing the metal hydroxide.
What are group 7 elements formally called?
Halogens.
The reactivity of the halogens …………… as you go down the group.
Identify the missing word.
Decrease.
How many electrons do the halogens have on their outer shell?
7 electrons.
Explain why larger atoms lose electrons easily going down the group.
When an atom gets larger, the electrostatic attraction between the nucleus and the outermost electrons of the atom decrease. This makes it more likely to be attracted to another atom with a strong enough electrostatic attraction.
How is the electrostatic attraction changed?
- Distance between outermost electron and nucleus.
- Number of occupied inner shells.
- Size of the nuclear charge.
State 3-4 physical properties of transition elements.
- Good conductors of electricity and heat.
- Hard and strong.
- High density.
- High melting point.
Explain why transition elements are useful in the industry.
They have good properties, such as being hard and strong, with a high density and being a good conductor of electricity and heat. This makes it viable for use in the manufacturing of everyday products.
