Chemistry Flashcards
What are the 3 states of Matter?
solid, liquid, gas
How does a solid change to a liquid?
melting
How does a solid change to a gas?
sublimation
How does a liquid change to a solid?
freezing
How does a liquid change to a gas?
boiling(evaporation)
How does a gas change to a liquid?
condensation
What is a melting point?
the temperature at which a substance changes from a solid to a liquid
What is a boiling point?
the temperature at which a substance changes from a liquid to vapour
Why do some substances melt easily whilst others need lots of energy?
Because the amount of energy needed to change state depends on the strength of forces between the particles of the substance.
What is a chemical bond?
the forces of attraction that bind atoms together in a molecule.
How are chemical bonds formed?
when valence electrons, the electrons in the outermost electronic “shell” of an atom, interact.
What are the 3 types of chemical bonds?
ionic,covalent, metallic
What is an Ionic Bond and example?
Electrons are transferred from metal to non-metal atoms to form positive and negative ions. These oppositely-charged ions are attracted to each other.(e.gNaCl)
What is a Covalent Bond and example?
A covalent bond is a shared pair of electrons that occurs in non-metal atoms. (e.g. I2, CH4)
What is a Metallic Bond?
The metallic bond is the strong electrostatic force of attraction between the positive metal ions and the ‘sea’ of delocalised electrons.(Cu)
Which chemical bond will form in brass?
Metallic Bond
Which chemical bond will form in Nitrogen Chloride?
Covalent Bond
Which chemical bond will form in Sulfur Dioxide?
Covalent Bond
Which chemical bond will form in Sodium Fluoride?
Ionic Bond
What is an Ion?
It is a charged atom caused by metals or non-metals transferring electrons.
What is a metal ions charge when losing an electron and what are they called?
Positively Charged they are called cations
How are the non-metal ions charged when gaining an electron and what are they called?
Negatively Charged they are called anions
How are the negative and positive bonds attracted to each other in Ionic Bonding?
Electrostatic Attraction
How do Covalent Bonds bond?
by sharing electrons
What is a Diatomic Molecule?
contain two atoms that are chemically bonded.
What are the 6 Diatomic Molecules?
Hydrogen,Nitrogen,Oxygen,Fluorine,Bromine,Iodine
What is a simple covalent molecule?
Molecules that consist of just a few atoms held together by covalent bonds
What is the approximate radius of an atom in satndard form?
1 × 10 (-10 m)
How do you work out an Ionic Compound?
- Write down the symbol for each element – the metal is always written first.
- Calculate the charge for each type of ion.
- Write the rate of the ions.
- Use the ratio to write down the formula of the ionic compound.
Why is Nitrogen a gas at room temperature?
Because it has weak intermolecular forces which makes it a gas.
What is a Polymer?
Polymers are very large molecules made from repeating units called monomers .
In general which metals would you expect to have the highest melting point Group 1 or 2?
Group 2 have higher melting points and boiling points – this is because they have 2 spare electrons and therefore there is a greater electrostatic force of attraction.
Give me 5 properties of metals?
High Density,Hard,Lustrous,High Tensile Strength,High Boiling and melting point,Ductile,Malleable,good conductors of heat and electricity
Who made the modern periodic table?
Dmitri Mendeleev
What are the 2 types of Ions?
Cations and Anions
What group is Halogens?
Group 7
What group is Noble Gases?
Group 0