C2.1 Structure and bonding Flashcards
What are compounds?
Substances in which atoms of two or more elements are chemically combined
What does chemical bonding involve?
The transferring or sharing of electrons in the highest occupied energy level (shell)
When atoms form chemical bonds by transferring electrons, what do they form?
Ions
What charged ion do atoms have if they lose electrons?
Positively charged ion
What charged ion do atoms have if they gain electrons?
Negatively charged ion
What electronic structure do ions have?
That of a noble gas (group 0)
What charge do group 1 form?
1+
What charge do group 2 form?
2+
What charge do group 3 form?
3+
What charge do group 4 form?
None, they usually form covalent bonds by sharing electrons
What charge do group 5 form?
3-
What charge do group 6 form?
2-
What charge do group 7 form?
1-
What charge do group 0 form?
None, they do not react with other elements to form ions as they already have full outer shells
What do elements in Group 1 (alkali metals) react with non-metals to form?
Ionic compounds in which the metal ion has a single positive charge
What do elements in Group 7 (the halogens) react with Group 1 (alkali metals) to form?
Ionic compounds in which the halide ions have a single negative charge
What is an ionic compound?
A giant structure of ions
What are ionic compounds held together by?
Strong electrostatic forces of attraction between oppositely charged ions
What is ionic bonding?
When two oppositely charged ions form strong forces of electrostatic attraction which act in all directions in the lattice
What is the structure of Sodium Chloride?
Sodium chloride contains Na+ and Cl- ions. The opposite charges are balanced and form strong forces of attraction holding them in a regular lattice structure
What bonds are formed when atoms share pairs of electrons?
Covalent bonds
Are covalent bonds strong?
Yes
Give some examples of simple molecular substances with covalent bonds
H2, O2, Cl2, H2O, HCl, NH3 and CH4
Give some examples of giant covalent structures
Diamond, silicon dioxide and graphite
What structure do metals have?
Giant structure
How are metals arranged?
In a regular pattern
What are the electrons in the outer shells of metal atoms?
Delocalised, so free to move through the whole structure
How are metals held together?
The positive ions and the negative electrons between them have strong electrostatic attractions holding the structure together
