Bonding, structure, and the properties of matter Flashcards
What are the three types of strong chemical bonds?
metallic, ionic and covalent
what is ionic bonding?
bond between a metal and a nonmetal they lose electrons to become stable
what is covalent bonding?
a bond that forms when two non-metal atoms share a pair of electrons
What is metallic bonding?
bond between two metals
delocalised electrons are free to move within the structure
How to work out the charge on the ions of elements in groups 1,2,6 and 7?
use the periodic table
How do you draw dot and cross diagrams?
element with a circle round it then dots and crosses to show electrons
Describe the structure of a giant lattice (reference forces)
strong electrostatic forces of attraction acting in all directions between the oppositely charged ions
What are the limitations of using dot and cross diagrams?
doesn’t show the 3D arrangement of the atoms and electron shells
What are the limitations of using ball and stick diagrams?
doesn’t show relative size of atoms and bonds
What are the limitations of using 2D diagrams?
does not show where ions are located on other layers
What are the limitations of using 3D diagrams?
not to scale
What are the different covalent substances?
some have small molecules and some have large molecules such as polymers and some have giant covalent structures such as diamonds and silicon dioxide
Describe the structure of a metallic lattice (reference positive ions and electrons)
the electrons leave the outer shell of metal atoms forming positive metal ions. the structure of the solid metal consists of closely packed metal ions arranged in a regular way.
Describe the particle model
the arrangement and movement of particles in solids liquids and gases
Describe the three states of matter using the particle model
solid - closely packed and vibrate
liquid - slightly more loosely packed and move in a fluid motion
gas - spaced out and don’t touch
explain changes in state using the particle model
chemical bonds between the particles form break or stretch
What determines melting and boiling point of different substances? (reference forces, particles, bonding and structure)
the stronger the forces between the particles the higher its melting and boiling points
What are the limitations of the particle theory in relation to changes of state?
It assumes that particles are the same in any substance so cannot adapt to mass or size or force of attraction to other particles.
What are the four state symbols and what do they mean?
S = solid
L = liquid
G = Gas
AQ = aqueous
Describe the structure of giant ionic lattice (reference to ions and electrostatic forces)
Regular arrangement of alternating positive and negative ions in a 3D shape.
What do ionic compounds have?
high melting and boiling points
What do ionic compounds not do when solid?
they don’t conduce electrify when solid but they do when melted or dissolved
What do substances which consist of small moles (gases or liquids) usually have?
relatively low melting and boiling points
What happens when small molecules melt or boil? (reference intermolecular forces present)
Weak intermolecular forces are overcome. Covalent bonds are not broken
How do intermolecular forces change as the size of the molecules increase and what effect does this have on the melting and boiling point of substances?
The bigger the molecule, the bigger its electron cloud meaning the greater the opportunity for intermolecular force.
What do small molecules not do?
they don’t conduct electricity
What are the properties of small molecules in terms of their structure and bonding?
strong covalent bonds that hold the atoms together
What do polymers have?
very large molecules
those molecules are linked to other atoms by strong covalent bonds
What is the relative strength of the intermolecular forces between polymer molecules and what effect does this have on their state at room temp?
strong compared to the intermolecular forces between smaller molecules
What do substances that consist of giant covalent structures have?
very high melting points
What are giant covalent structures linked by?
very strong covalent bonds
What are the properties of giant covalent structures in terms of their structure and bonding?
high melting point as it takes a lot of energy to break the strong covalent bonds between the atoms
they cannot conduct electricity as they have no overall charge
What happens to giant covalent structures when they melt or boil? (reference covalent bonds present)
large amounts of energy are needed to overcome their strong covalent bonds to make them melt or boil
What are some examples of giant covalent structures?
diamond, graphite and silicon dioxide
What do metals have?
giant structures of atoms with strong metallic bonds
What do metallic bonds mean?
most have high melting and boiling points?
Whats the arrangements of atoms in pure metals?
neat layers
What are the properties of metals in terms of their structure and bonding?
arranged in a regular pattern and are closely packed together
What is an alloy and how are the atoms arranged?
Atoms of different sizes, this distorts the layers.
What are metals good conductors of?
electricity and thermal energy
Describe the structure of a diamond
giant covalent structure in which each carbon atom is joined to 4 other carbon atoms by strong covalent bonds
What are some properties of diamonds in terms of its structure and bonding?
very hard
very high melting point
^ ( strong covalent bonds)
doesn’t conduct electricity ( no free carbon bond)
Describe the structure of graphite?
layers of carbon atoms arranged in 6 membered hexagonal rings
each carbon atom forms 3 covalent bonds with other carbon atoms leaving one free bond
what are properties of graphite in terms of its structure and bonding?
soft and slippery (organised in layers)
high melting point (strong covalent bonds)
Conducts electricity (free carbon bond)
Describe the structure of graphene
a single layer of carbon atoms tightly bound in a hexagonal honeycomb lattice
What do the properties of graphene make it useful for?
electronics and composites
What are the properties of graphene in terms of its structure and bonding?
very high melting point and very strong because of its large regular arrangement of carbon atoms joined by covalent bonds
Describe the structure of fullerenes
composed entirely of carbon
What was the first fullerene to be discovered?
Buckminsterfullerene ( sphere shape )
What do the properties of fullerenes make theme useful for?
nanotechnology, electronics and materials
What does nano science refer to?
structure that are 1-100nm in size
As the side of a curb decreases by a factors of 10 what happens?
the surface area to volume ratio increases by a factor of 10
Why do nano particles have properties different from those with the same materials?
high surface area over volume ratio
What do nano particles have?
applications in medicine, electronics, cosmetics, suncreams, deodorants and catalysts
What are advantages and disadvantages of the applications of nano particle materials?
offers the potential for newer faster kinds of computers, more efficient power sources and lifesaving medical treatments
economic disruption and possible threats to security, privacy, health and the environment
What are the possible risks associated with the use of nano particles?
if you inhale them it may cause lung inflammation and heart problems
