SC5-7 Flashcards
What are ions?
An atom or group of atoms with an electrical charge due to the gain or loss of electrons.
Why do atoms lose or gain electrons?
They’re trying to get a full outer shell (stable electronic structure)
What are positive and negative ions called?
+ = cations
- = anions
When do negative ions (anions) form?
When atoms gain electrons - they have more electrons than protons.
When do positive ions (cations) form?
When atoms lose electrons - they have more protons than electrons.
What groups are the most likely to form ions?
1&2 and 6&7
What ions do group 1&2 form?
They lose electrons so form positive ions.
What ions do group 6&7 form?
They gain electrons to form negative ions.
What happens to the electrons if a metal and non-metal react together?
The metal atom loses electrons to form a positive ion (cation) and the non-metal gains the electrons to form a negative ion (anion).
What is ionic bonding?
Transfer of electrons.
What diagram is used to show how ionic compounds are formed?
Dot and cross.
What structure do ionic compounds have?
They ions form a closely packed regular lattice structure.
What are the similar properties between ionic compounds?
- Strong electrostatic forces of attraction between oppositely charged ions.
- They have a high melting and boiling point due to the strong attraction between the ions. It takes a large amount of energy to overcome this attraction.
- Solid ionic compounds don’t conduct electricity because the ions are fixed in place and can’t move, but when the ions are free to move, they will carry an electrical current.
- Many dissolve easily in water. The ions separate and are all free to move in the solution, so they’ll an electrical current.
What is a covalent bond?
Its a strong bond that is formed when a pair of electrons is shared between two non-metal atoms.
What diagram is used to show covalent bonding?
Dot and cross.