Unit 1 exam Flashcards
What is the correct chronological order of discovery?
Protons, nucleus, electron, neutron
The periodic table is compiled by arranging elements in increasing order of
Atomic number
What is the ionisation trend?
ionisation energy increases as it goes across and upwards
What allows a substance to be a gas at room temp?
Boiling point lower than 25 degrees C at room temp
How can you tell if a compound is ionic by it’s conductivity?
If a compound does conduct electricity when dissolved in solution or molten it is ionic, if not then it is covalent
How do you know is a compound is polar?
The greatest difference in electronegativity will correspond to the most polar bond
How to calculate the number of neutrons in element
mass number - atomic number
Why are metals able to conduct electricity in a solid state?
Metals are immersed in a ‘sea’ of negatively charged delocalised electrons
What type of bonds are broken when ice is melted?
Bonds between molecules = intermoleculer bonds
Answer : Hydrogen
Do groups go up and down or across?
Up and down, whereas periods go across
How to find the number of electronic shells are around an element
Period number = number of shells
Electronegativity trend
Lowest = bottom left corner Highest = top right corner
Which one of Dalton’s theory is correct?
- Compounds are formed by a combination of two or more different kinds of atoms
- All atoms of a given element are identical in mass and properties
- A chemical reaction is a rearrangement of atom
- All matter is made of atoms. Atoms are indivisible and indestructible.
1,3
Why is “all matter is made of atoms. Atoms are indivisible and indestructible” not valid today?
Atoms can be divided up, division of nucleus in nuclear reaction
