C4: The Periodic Table Flashcards
How is an ionic bond formed?
When a metal reacts with a non metal, ions are transferred from the metal atoms to the non metal atoms. As a result, there will be positively charged metal ions and negatively charged non metal ions. Because the ions are oppositely charged, there is a strong force of attraction between them - forming an ionic compound.
How is a covalent bond formed?
Covalent bonds are formed between non metal atoms that share electrons.
What is the charge and mass of an electron?
Charge is -1
Mass is 0
What is the charge and mass of a proton?
Charge is 1
Mass is 1
What is the charge and mass of a neutron?
Charge is 0
Mass is 1
What is an isotope?
A variety of an element with a different atomic mass but the same atomic number
Why do metal atoms usually form positive ions?
Metal ions form positive ions because they lose electrons in their outer shell in an attempt to become more stable
Why do non metal atoms usually form negative ions?
Non metal ions form negative ions because their outer shell gains electrons in an attempt to become more stable
Why does sodium chloride have a high melting point?
Sodium chloride has a high melting point because of the strong attraction between oppositely charged ions in a giant ionic structure. It takes a lot of energy to overcome these attracted forces, meaning sodium chloride has a high melting point
Why does magnesium oxide have a higher melting point than sodium chloride?
- MgO has a higher melting point than NaCl because it is made up of Mg2+ and O2- ions, as opposed to being made up of Na+ and Cl- ions.
- The fact that the ions in MgO have double the charge means that the attraction between them is harder to over come.
- Furthermore, the O2- ions are smaller than the Cl- ions, meaning that the ions in MgO can be pact together more closely.
- This makes the forces of attraction harder to overcome.
Why do molten and dissolved NaCl conduct electricity while solid NaCl cannot?
When NaCl melts or dissolves, the ions are free to move and therefore they will be able to conduct electricity.
What is a giant ionic structure?
A large structure of positive and negative ions that are strongly attracted to each other.
Why do carbon dioxide and water have low melting and boiling points?
They are simple molecular structures. While they have very strong covalent bonds between the atoms, the intermolecular forces between the molecules are relatively weak. As a result, the molecules can be easily parted.
Therefore, less energy is needed to separate them (boil or melt).
Why are alkali metals stored in oil?
They react vigorously with water, meaning they have to avoid contact with it to prevent safety hazards. Oil acts as a barrier between the alkali metal and the water.
What is the flame test colour for lithium?
Red
What is the flame test colour for sodium?
Yellow/Orange
What is the flame test colour for potassium?
Lilac/Purple
What is the general word equation for an alkali metal with water reaction?
alkali+water–>hydroxide+hydrogen gas
What is the symbol equation for the reaction between sodium and water?
Na+H2O–>NaOH+H2
it then needs to be balanced
Why do alkali metals all have similar properties?
low melting point, low density, very soft
They are all keen to lose an electron and form positive ions with stable electronic structures.
Why do alkali metals become reactive as you go down the periodic table?
As you go down group 1, alkali metals become more reactive because the outer electron is more easily lost - this is because it’s outer shell is further from the nucleus (larger atomic radius), so less energy is needed to remove it.
What is oxidation?
Loss of electrons
How might you set up a flame test to identify alkali metals?
- Dip a wire loop into some hydrochloric acid to clean and moisten it
- Put the loop into a powdered sample of the compound to be tested, and then place in the end in a blue bunsen flame
- The flame will change colour depending on which alkali metal is present
What is the physical appearance of chlorine at room temperature?
Green Gas