Atoms into ions Flashcards
What is a compound?
A compound contains 2 or more elements which are chemically combined.
What is an example of two substances you can mix without a chemical reaction?
Sand and copper sulfate
What is the name of the group with a stable electronic configuration?
The noble gases
When atoms are unstable they…
…react to take part in changes which give them a stable arrangement of electrons.
To maintain a stable electron configuration they may either…
- share electrons, which is called COVALENT BONDING
- transfer electrons, which is called IONIC BONDING
In ionic bonding atoms…
lose of gain electrons to form charged particles called ions
What electronic structure do the ions have?
The electronic structure of a noble gas.
e.g if sodium (2,8,1) loses one electron, it is left with the stable electronic structure of neon (2,8)
What does an atom become when it loses an electron in ionic bonding?
It becomes a positively charged ion because there are now more protons than electrons
What is the formula of a sodium ion?
Na+
What two substances react with each other in ionic bonding?
A non-metal and a metal
When non-metals react with metals, which one gains electrons?
The non-metal gains electrons and the metal tends to lose electrons
In ionic bonding when the non-metal atoms gain electrons, what do they become?
Negatively charged ions
What is the name of the forces that hold together positively and negatively charged ions?
Electrostatic forces of attraction
What do the elements in group 1 react with and why?
They react with group 7 elements as group 1 element only have one electron in their outer shells and need to lose it whereas group 7 elements have 7 electrons in their outer shells and need to gain one in order to gain the stable electronic structure of a noble gas.
What do electrostatic forces of attraction result in?
A giant lattice structure
What do group one elements form?
1+ ions
What do group 2 elements from?
2+ ions
What do group 3 elements form?
3+ ions
What do group 4 elements from?
Group 4 do not form ions (apart from tin (Sn) and lead (Pb) at the bottom of the group)
What do group 5 elements form?
3- ions, when they form ions as opposed to sharing electrons
What do group 6 elements form?
2- ions, when they form ions as opposed to sharing electrons
What do group 7 elements from?
1- ions, when they form ions as opposed to sharing electrons
What do group 0 elements from?
Group 0 never forms ions in compounds
What is another example of ionic bonding?
Calcium chloride. Each calcium atom needs to lose 2 electrons but each chlorine atom only needs to gain 1 so EACH calcium atom gives 1 electron to one chlorine atom and another to another chlorine atom. An ion made up of a group of atoms is called a COMPOUND ION.
Apart from group 1 and group 7 what groups can form ionic compounds?
Group 2 (forming 2+ ions) and group 6 (forming 2- ions)
In what direction do electrostatic forces operate?
All directions
Why do ionic compounds have high melting and boiling points?
It takes a lot of energy to break up a giant ionic lattice. There are lots of strong ionic bonds to break. To separate the ions you have to overcome all those electrostatic forces of attraction acting in all directions.
Why do ionic compounds conduct electricity when molten or dissolved in water?
Once you have supplied enough energy to separate the ions from the lattice, they become mobile so can start to move around. This is when the ionic solid melt and becomes a liquid. The ions are free to move anywhere in this liquid. They are attracted to oppositely charged electrodes held in the molten compound. Therefore, they can carry their electrical charge through the liquid. In a solution water molecules separate ions from the lattice so it is the same principle.
Why can’t a solid ionic compound conduct electricity?
Because its ions are held in fixed positions in the lattice.
