chem Flashcards
(38 cards)
what are Elements ?
They are a single type of atom
what are compounds ?
2 or more elements that are chemically bonded
where are electrons located and what is the mass and charge of it ?
on outer shell –> mass = 1/2000 , charge = -1
where are protons located and what is the mass and charge of it ?
in the middle (nucleus) –> mass = 1 , charge = +1
where are neutrons located and what is the mass and charge of it ?
in the middle (nucleus) –> mass = 1 , charge = 0
How can we tell if the number is an atomic number and what does it represent ?
smaller number = protons and electrons (not added)
How can we tell if the number is an mass number and what does it represent ?
larger number = protons + neutrons
who discovered protons ?
Rutherford
who discovered neutrons ?
James Chadwick
who discovered nucleus ?
Rutherford
who discovered electrons ?
J.J. Thomson
who discovered the current model we know today ?
Bohr
Tell me 3 things about Dmitri Mendeleev’s table and what has changed ?
- was sorted by mass and similar patterns
- left gaps
- he predicted properties
(but now we arrange it in electronic arrangements – subtle difference)
what it the formula for
- Carbon dioxide
- water
- oxygen gas
- hydrogen gas
- nitrogen gas
- ammonia
- hydrochloric acid
- sulfuric acid
- CO2
- H2O
- O2
- H2
- N2
- NH3
- HCI
- H2SO4
Tell me 5 things about Halogens.
- In group 7
- Non metals
- Only need to gain one electron so very reactive
- Most reactive on top and least reactive in bottom
- Low boil on top and high boil on bottom
Tell me 4 things about alkali metals.
– group 1
- least reactive on the top but most reactive in the bottom
- high melting point on the top but low melting point in the bottom
- Soft grey metal – need to be kept in oil so it doesn’t react with oxygen or water in the air
Tell me 3 things about Nobel gases.
- group 8/0
- Has full outer shell
- meaning it’s Unreactive
what does the state symbol (Aq) stand for ?
aqueous
From it’s structure why can pure metals conduct electricity and can conduct heat ?
Pure Metals are made up of positive atoms in a sea of delocalized electrons which are free to move meaning the metals can conduct electricity and be a really good source of conducting heat.
Are pure metals soft or hard ? why ?
Pure metal has layers that can slide across each other and because of this they are soft.
Are alloys soft or hard ? why ?
Alloys either have no layer or distorted layer and they cannot slide meaning they are hard.
Explain the structure of an alloy ?
An alloy has the same things as a pure metal (positive atoms in a sea of delocalized electrons) but it also includes another metal or e.g. carbon that is alloyed with.
what’s the molecule formula for Octane ?
C8H18
what’s the molecule formula for hexane ?
C6H14
