properties of solids very important Flashcards
Define lattice structure
The forces of electrostatic attraction between ions in a compound cause the ions to surround themselves with ions of opposite charges, and as a result forming a 3D shape called lattice structure
Coordination number
Coordination number = expresses number of ions that surround a given ion in the lattice.
ex) sodium chloride has the coordination number of 6 because each NA+ is surrounded by six Cl- ions and each Cl- ion is surrounded by 6 NA+ ions
What is the formula unit?
An expression of the ratios of ions present
Ionic crystals charcteristics
- Melting and boiling point
- Volatility(tendency of a substance to vaporize)
- Electrical Conductivity
-Brittleness
High boiling point
explanation:
The forces of electrostatic attraction between the ions in the lattice are strong and so require large amount of heat energy to break.
Ionic compounds are generally soluble:
because they have a greater attraction to the partial positive parts of liquids ex water
low volatility
Ionic compounds do not conduct electricity in solid state, but can in aqueous due to the ions being closely held together due to the strong lattice forces and when they are in liquid state, the electrons are more mobile making compound conduct able
explanation: is in the text
ionic compounds are usually brittle
- If a large enough force is applied to the compound it causes ions to shift along a layer which displaces that structure and therefore, there will be the repulsion between like charges with ionic compounds. Because the ionic solids are localized, these solids tend to be stiff and brittle like covalent solids.
Molecular compounds have physical properties that depend on their shape and chemical makeup. Why is the polarity an important factor in the physical properties molecular compound displays
Polarity is an important factor in the physical properties of molecular compounds because if two elements are sharing an electron, the element that is more negatively polar will attract the electron longer, changing the shape of the molecule
Why are non polar molecules able to dissolve fast in non polar solvents but not in polar solvents
and then why are non polar able to dissolve when in non polar solvents
These molecules don’t have regions of partial positive or partial negative charge and therefore have trouble bonding with water for example to dissolve. The H bonds and intermolecular forces are to strong to be altered by just a mere LDF force
because of the LDF forces between solute and solvent
Why dont non polar molecules conduct well
not sure
Why do polar molecules have a higher boiling point
The stronger the intermolecular forces, the more energy required to break them apart resulting in higher boiling point
Why are polar molecules able to dissolve fast in polar solvents but not in nonpolar solvents
and then why are polar able to dissolve when in polar solvents
The solute and solvent interact through dipole dipole and H bonds
Polar substances do not mix well as they are closely held together by their H bonds and dipole dipole forces that keep them together
What is a network solid
A solid that consists of atoms held together in large networks or chains by covalent bonds.
What is an allotrope
Allotropes are different forms of an element in the same physical state such as oxygen and ozone both O2 and O3
Why are Graphite, diamond, fullerene C60, and graphene considered to be allotropes?
They all contain the same element of Carbon, although they do differ in their number of carbons which is slightly irrelevant, they are both in the same state(solid) making them allotropes.
Know about graphite diamond fullerene and graphene
yay
why are metal bonds referred to as having a “sea of electrons” explain using the term delocalized electrons
Metal solids are often referred to having “a sea of electrons” as the electrons are delocalized, moving freely (no longer fixed on one position) and can spread themselves throughout the metal structure
what are the three factors that affect Metallic bonding strength
of delocalized e-s,
charge of the cation,
radius of the cation.
