Chemical Bonding and Structure Flashcards
What is metallic bonding
Is the electrostatic forces of attraction between metal cations and a sea of delocalised electrons
What are the 5 properties of metals
- conduct electricity
- malleable
- ductile
- high melting and boiling temperatures,
- good thermal conductors
What effects the ability of metals to conduct electricity and melting point
The more delocalised electrons there are the better they conduct electricity and the higher the melting point
What is ionic bonding
•Is the electrostatic forces of attraction between oppositely charged ions
The strength of ionic bonding depends on
What has this got to do with charge density
The bigger the charge on the ion, the stronger the electrostaic forces between ion
The smaller the ion, the stronger the electrostattic attraction between ions, as they can pack together more tightly
Having a small ion and large charge, will lead to a high charge density
Does ionic radii, increase or decrease down a group
•Ionic radii increases down group
Due to the addition of electron shells, so ionic radii increases
What are the 3 main properties of ionic compounds
high relatively high melting temperatures due to strong electrostaitc forces
can conduct electricity when molten or in aqueous solutions due to ions being able to move around
brittle, as layers can slide
Dissolve in water, as water molcules are polar, and attract the negative and positive ions
Are ionic compounds soluable in water
and why
- Ionic compounds are soluble in water because the positive ions will separate and becomes surrounded by electronegative oxygen molecules forming and ion-dipoles interaction.
- Negative ions will be removed from the lattice and become surrounded by hydrogen molecules forming hydrogen bonds.
- The energy for this is supplied by hydration energy
Evidence for ionic compounds can be found where
via electrolysis where the ionic molecules is dissolved in water and the positive ions will move toward the anion and the negative ions move towards the cation
What is covelent bonding
Is the electrostatic forces of attraction between nuclei of two atoms and the bonding pairs of electrons
How are covelent bonds formed
formed the overlap out their outer shell orbitals containing a single electrons
The area of overlap 2S orbitals is called
a sigma bond
The area of overlap in 2P orbitals is called a
Sigma bond
The area of overlap sideways between two P orbitals is called
Pi bond
A pi bond results in a what in a covalent bond
high electron density above and below the molecule
Bond length is
Is the distance between two nuclei of the two atoms covalently bonded
Bond strength is determined by
the amount of energy required to break a mole of bonds in gaseous state
The stronger the bond, the longer or shorter the length ?
•The stronger the bond the shorter the length
Nuclei with increased what, will have a greater bond strength
electrostatic attraction
What is electronegativity
•Is the ability of an atom to attract a bonding pair of electrons
What is the trend in electronegativity down a group and across a period
•This decreases down a group and increases across a period
Do molecules of the same element have the same or different distribution of electron density?
•Molecules of the same element have the same distribution of electron density
What is a polar covelent bond
•Polar covalent bonds is where there is a unsymmetrical distribution in electron density, due to a covalent bond with one atom carrying a slightly negative change and the other one positive
A polar covalent bond, is a covalent bond with a degree of
ionic character