Chemistry No2 Flashcards
What is group 1
Alkali metals, metals
What is group 2
Alkaline earth metals, metals
What is group 7
Halogen, non metals
Groups go….
Down
Periods go…..
Across
Where is the separating staircase on the periodic table
From Boron (including)
Experiment to see if something is a metal?
Conduction : This experiment tests the conduction of electricity by clipping the substance onto two wires and attaching it to a circuit to see if the bulb will still light up
Heat: The second experiment tests if the substance conducts heat. To do this, you get a beaker of hot water and put the materials in. You then start the clock and touch the ends of the substances to see if they are warm.
What is the order of reactivity in Alkali metals
Lithium Sodium Potassium Rubidium Caesium
As you go down, they get more reactive
Where are they stored and why?
All the alkali metals are stored in oil to prevent them reacting with the oxygen in the air.
What does lithium look like, feel like
Black
When cut: silver
Hardness. Soft
What does sodium look like, feel like?
Black
When freshly cut: silver
Hardness: Softer
What does potassium look like, feel like
Black
When freshly cut: silver
Hardness: softest
Lithium reaction with water
Lithium- when Lithium reacts with water it floats, then fizzes steadily and becomes smaller, it then eventually disappears.
Sodium reaction with water
Sodium-when sodium reacts with water it melts to form a ball that moves around the surface. It fizzes rapidly, and the hydrogen produced may burn with an orange flame before the sodium disappears.
Potassium reaction with water
Potassium- when potassium reacts with water, the metal melts and floats. It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with sparks and a lilac flame. There is sometimes a small explosion at the end of the reaction.
Word equation for group 1 reactions with water
Metal + water ——> metal hydroxide + hydrogen
Why do the elements in group 1 get more reactive as you go down
They loose an electron and the further away the electron is from the nucleus, the easier it is to loose on because there is less attractive force between them.
Test for hydrogen
When testing for hydrogen, you need to light a splint. Then you put the splint down the test tube and if hydrogen is present then a pop will be heard or a squeaky sound. If hydrogen is not present then a pop will not be heard.
Group 2 reactions with water
The metals disappear.
Check other flashcards
Group 2 word equations when mixed with water
magnesium + water —> magnesium hydroxide + hydrogen
calcium + water —> calcium hydroxide + hydrogen
strontium + water —> strontium hydroxide + hydrogen
Reactivity in group 2 (compared to group 1)
Trend in reactivity:
Each element gets more reactive as you go down the list. AKA: Magnesium is more reactive than calcium
AKA: Lithium is more reactive than magnesium
Group 1 is more reactive than group 2.
What does chlorine look like
Pale green gas
Toxic
What does bromine look like.
Dark red liquid
Toxic + corrosive
What does iodine look like?
Grey solid
Hazardous
When heating sublimes (changes directly into vapour)
Diatomic molecules
Two atoms thatvare the same chemically bonded together
What is formed when a halogen reacts with a metal?
When a halogen reacts with a metal a halide is formed
Diatomics
The Diatomic Elements are molecules composed of 2 atoms. The famous pneumonic to help remember the elements that are diatomic is:
“HAVE NO FEAR OF ICE COLD BEER” H2 - Hydrogen N2- Nitrogen F2- Fluorine O2- Oxygen I2 - Iodine Cl2- Chlorine Br2 - Bromine
Group 7 reactions with wool observations
Chlorine - Burning, sparks, flame producing an orange gas. Iron goes yellow. Orange gas = iron chloride
Bromine - Bit of flame (less then chlorine), glows, goes brick red. Orange gas
Iodine - Sublimation, purple gas, no sparks, gas produced
Group 7 reactions with wool equations
Chlorine + iron —> iron chloride
Bromine + iron —> iron bromide
Iodine + iron —> iron iodide
Group 7 trend in reactivity
Each outer shell contains seven electrons and when group 7 metals react, they will need to gain one outer electron to get a full outer shell of electrons. As you go up group 7, the number of shells of electrons decreases (period number decreases up the Periodic Table)
The reactivity of halogens decrease down group u, this is because the electron shells have a repulsive effect on the reacting electron, weaking the force
Structure of an atom
The atom is made up of three parts: protons, neutrons and electrons.
The protons and neutrons are in the nucleus, and the electrons are in the shells around the nucleus.
Relative charge and mass of different parts inan atom
Protons - mass = 1, charge = +1
Electrons - mass = 1/2000, charge = -
Neutrons - mass = 1, charge = 0
Define the terms atomic number, mass number and isotopes
The mass number is the top number and shows the total amount of protons and neutrons.
The atomic number is how many protons (or electrons) are in that element.
An isotope is a type of element that can differ in neutron number. This means that there is a decimal in the mass number
Relative atomic mass equations
(((Mass number of isotope 1) x (percent abundance of isotope 1)) + ((mass number of isotope 2) x (percent abundance of isotope 2)))/ 100
Define relative atomic mass and show how to calculate it
Relative atomic mass is the average mass of one atom and for isotopes (elements with two forms) it can be hard to calculate so there is a simple formula:
The percent is how many atoms in the form of isotope one/two per 100 atoms of that element. This will always be given to you.
Show maximum number of electrons in the first 3 shells. Draw the electron arrangement for calcium.
In the first shell there is maximum 2 electrons, in the second there is maximum 8 and in the third there is also maximum 8.
The electron configuration for calcium is 2, 8, 8, 2
How is electron arrangement related to position on the periodic table?
The columns of the periodic table are called groups.
The rows of the periodic table are called periods.
Atoms in the same group have the same amount of electrons in their outer shell.
Atoms in the same period have the same amount of shells.
Define atom and element (with a particle picture)
- An Atom is the smallest particle that things are made of.
- An element is a substance made up of only one type of atom.
Define compound
COMPOUND: Two or more different atoms that are chemically bonded (joined)
Define mixture
A mixture is something made up of two or more elements and/or compounds not chemically joined
Define molecule (with 2 particle pictures, one an
element and one a compound)
A molecule is a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction. two or more non-metal atoms bonded together
What is the difference between a molecule and a compound
Molecule is the general term used to describe any atoms that are connected by chemical bonds. Every combination of atoms is a molecule. A compound is a molecule made of atoms from different elements. All compounds are molecules, but not all molecules are compounds.
Why does mass appear to increase or decrease in reactions?
In reactions, mass sometimes appears to decrease because oxygen or any other form of gas escapes from the mass of the other reactants in the experiment.
Mass sometimes appears to increase because oxygen from the atmosphere is added and oxygen has a mass. This mass is added to the mass of the other products increasing the overall mass.
What are the state symbols and what do they mean
s)
Solid
(l)
Liquid
(g)
Gas
(aq)
Aqueous (dissolved in water)
What is the conservation of mass?
The law of the conservation of mass is that mass cannot be created or destroyed. Mass is always conserved but might be different at the end of an equation than the beginning.
Will the mass appear to increase or decrease in these examples?
● zinc reacts with dilute hydrochloric acid to produce zinc chloride solution and hydrogen gas, which then escapes - it will decrease as the zinc chloride solution and hydrogen gas escape.
● magnesium reacts with oxygen, gained from the air, to produce magnesium oxide- it will increase as it gains oxygen
Define a hydrocarbon and give 2 examples
A hydrocarbon is a chemical substance which contains only hydrogen and carbon atoms chemically bonded together. Two examples are methane and octane.
What is the source of hydrocarbons?
Hydrocarbons are organic compounds made up of two elements (carbon and hydrogen) only, hence their source name. The main source of hydrocarbons is crude oil. There are many hydrocarbons.
Give some uses for hydrocarbons
They are used for fuel. Gasoline, natural gas, fuel oil, diesel fuel. They can be used to make things, including plastics, synthetic fabrics and polyester. An example of a hydrocarbon is butane which is a petrochemical and petroleum refinery for feedstock; motor gasoline blending. Also Ethane is used for petrochemical feedstock for ethylene production and power generation.
What is combustion?
Combustion is a type of chemical reaction between fuel and an oxidant, where then the substance gets oxidised by burning. In other words, combustion reactions occur when oxygen reacts with another substance and gives off heat and light.
Give a word equation for combustion
Hydrocarbon + oxygen -> carbon dioxide + water
How do you test for water?
When there is present in a copper sulphate sample the copper sulphate (usually white) turns blue instead. This shows that there is water present.
How do you test for carbon dioxide?
Bubble it through lime water
If it goes cloudy, CO2 is oresent