2A. Bonding and Structure [SET 1] Flashcards
What is ionic bonding?
The strong electrostatic attraction between oppositely
charged ions
What effects does ionic radius have on the strength of ionic bonding?
The smaller the radius, the stronger the ionic bond
What effects do charges have on ionic bonding?
The greater the charge, the stronger the bond
How are ions formed?
By the loss (+) or gain (-) if electrons
What is a cation?
A positively charged ion
What is an anion?
A negatively charged ion
What does isoelectronic mean?
Two or more molecular entities that have the same number of electrons or a similar electron configuration
How does a positive charge affect atomic radius?
It gets smaller because it loses electrons from its outer shell
How does a negative charge affect ionic radius?
It gets larger because electrons are added to the outer shell
What are the trends in atomic radii for ions with different charges?
The larger the charge, the bigger the change in the ion’s size
How can the migration of ions be observed?
During electrolysis of coloured compounds
What does ionic migration prove?
The existence of ions
What are the melting/ boiling temperatures if ionic compounds like?
They’re high due to the dying bonds
What are ionic compounds like physically?
They’re hard, brittle, crystalline substances
How soluble are ionic compounds?
They’re soluble in water and other polar solvents but insoluble in non polar solvents
Do ionic compounds conduct?
Not when solid, because their ions cannot move away from their fixed positions, but they do conduct when melted or dissolved
What happens when ions reach the anode?
They lose electrons
What happens when ions reach the cathode?
They gain electrons
What is a covalent bond?
The strong electrostatic attraction between two nuclei and the shared pairs of electrons between them
What is a dative covalent bond?
One in which both the electrons in the bonding pair are provided by one atom
What do lone pairs of electrons do?
- Affect the shapes of molecules
- Are used to form dative covalent bonds
- Are important in the chemical reactions of some compounds including water and ammonia
What is bond length?
The distance between the nuclei of two bonded atoms in a molecule
How can bond lengths be measured?
Using X-Ray diffraction when solid or Microwave spectroscopy when gaseous
What does bond length depend on?
The size of atoms involved and the number of pairs of electrons shared
Why do large atoms form longer bonds?
Because they have more electrons which shield the nuclei and reduce the attraction for the electron cloud.
Single bonds are…
…longer than double bonds, which are longer than triple bonds
Why are triple bonds shortest?
The nuclei can remain closer together if the shared electron cloud contains more electrons to overcome the repulsion of the nuclei