C2.2 - Bonding Flashcards
What are typical properties of metals?
- Shiny
- Usually high MP and BP
- Solid (apart from mercury)
- Malleable
- Ductile
- Good conductors
What are typical properties of non-metal elements?
- Dull
- Usually low MP and BP
- About half are solid and half are gas at room
temperature - Brittle
- Non-ductile
- Poor conductors
- Insulators
How can metals and non metals be separated on the periodic table?
They can be separated by a zigzag boundary starting from under Boron.
What are chemical properties of a substance?
A chemical property is a characteristic of a substance that can only be determined by studying its chemical reactions.
What are two chemical properties of metals and non metals?
- Metals lose electrons to form positive ions, but
non- metal atoms gain electrons to form negative
ions. - Metal oxides produce alkaline solutions if
dissolved in water. - Non-metal oxides produce acidic solutions if
dissolved in water.
What does the electron structure of an element show?
The electronic structure of an element shows how the electrons are arranged in atoms.
What is the outer shell?
The outermost occupied shell in an atom is called the outer shell.
How is electron structure related to the Periodic Table?
- The last number equals the non-IUPAC group
number. - The number of numbers equals the period
number. - The sum of the numbers equals the atomic
number.
What is an ion?
An ion is a charged particle formed when an atom, or group of atoms, loses or gains electrons.
How do metals and non-metal form ions?
- Metal atoms lose electrons to form positive
ions. - Non-metal atoms gain electrons to form
negative ions. - Non metals and metals gain or lose electrons to
make a complete outer shell.
What does an electron diagram show and how do you draw one?
- An electron diagram represents the electronic
structure of an atom or ion. - Circle to represent each shell.
- Dots or crosses to represent its electrons - To also
represent which electrons are gained. - Charge written outside the brackets on the top
right. - Element symbol written in the centre
How do ionic compounds form?
- When a metal reacts with a non-metal, electrons
are transferred from the metal atoms to the non-
metal atoms so that they both achieve more stable
electronic structures. - Metal atoms become positively charged and non-
metals atoms become negative ions.
How can you model ionic compounds?
- You can model the ions in the ionic compounds
that is formed using a dot-and-cross diagram. - Electrons from one atom as dots.
- Electrons from the other atom as crosses.
What is the structure and bonding in ionic compounds?
- Giant ionic lattice.
- A structure of ionic compounds in which
oppositely charged ions are held in a regular and
repeating arrangement by strong electrostatic
forces of attraction. - Ionic bonding - Strong electrostatic forces of
attraction between oppositely charged ions.
What are the limitations of a ball-and-stick model representing an ionic compound?
- Ions are actually close together.
- Bonds are forces rather than physical objects
made from matter.
What is a covalent bond?
A covalent bond is a strong electrostatic force of attraction between the nuclei of two (bonded) atoms and their shared pair(s) of electrons.
How can covalent bonds be modelled?
- Using a dot-and-cross diagram.
- Electrons from one of the bonded atoms are
shown as dots. - Electrons from the other bonded atom are
shows as crosses - Each pair of electrons in the shared area
between the overlapping circles represent a
covalent bond. - Only outer shells are usually shown.
What is a simple molecule?
A molecule that contains only a few non-metal atoms covalently bonded.
What is the difference between the covalent bonds and the intermolecular forces of a simple molecule?
- Covalent bonds between the atoms in a simple
molecule are strong. - Intermolecular forces between the molecules are
weak.
What are the limitations of a displayed formula of a simple molecule?
Simple molecule have shapes, however a displayed formula does not show the three-dimensional shape of the molecule.
What is a giant covalent structure?
An arrangement of very many non-metal atoms joined by covalent bonds in a regular repeating arrangement.
How does diamond exist?
- As having a giant covalent structure.
- Each carbon atom is joined to four other carbon
atoms by covalent bonds.
How do you write the chemical formula of ionic compounds and giant covalent structures?
You use the empirical formula as there are many ions/very many atoms involved and it makes little sense to write a chemical formula with the huge numbers.
What is a polymer?
A substance with molecules made from many repeat units.
What are monomers?
Small, simple molecules that can join together in chemical reactions to form polymer molecules.
How can you model monomers?
- Dot and cross diagram.
- Displayed formula.
- Ball and stick model.
What is a thermosoftening polymer?
- Each polymer molecule is drawn as a wavy line
(in diagram). - Weak intermolecular forces.
- Polymer chains are relatively easy to separate.
What is a thermosetting polymer?
- Each polymer molecule is drawn as a wavy line.
- Cross linking.
- Chains joined by strong covalent
bonds.
What is the structure of metals?
- All metals apart from mercury are solid at room
temperature. - Their ions are packed together in a regular way,
forming a giant metallic lattice.
What are metallic bonds?
Metallic bonds are the strong electrostatic forces of attraction between the delocalised electrons and the closely packed, positively charged nucleus.
What are delocalised electrons?
The ‘sea’ of electrons around the positively charged metal ions in the structure of a metal.
What did Mendeleev consider before making his first table?
- The atomic weights of the known elements, similar
to our modern relative atomic masses. - Knowledge of the chemical reactions of different
elements. - Knowledge of physical properties, such as
melting points and boiling points
How did Mendeleev arrange the elements in his periodic table?
- In order of increasing atomic weight.
- Grouped together the ones with similar
chemical properties. - Swapped tellurium and iodine because he felt
that this matched their chemical properties
better. - Left out spaces for elements he though would
exist but were not yet discovered, and predicted
their properties from those of nearby elements. - Died before proton was discovered.
- Henry Mosely discovered that an atom’s atomic
number was actually the number of protons in
its nucleus.
Why did Mendeleev not accept inert gases at first?
Mendeleev thought that elements should be able to react with other elements, so he was reluctant to believe that helium and argon were elements.
What is electronic structure determined by and what does it determine?
- Electronic structure is determined by the
number of protons. - The electronic structure of an element
determines its chemical properties.
What happens as you go down group 1,2 and 7 of the periodic table?
- Elements in group 1 and two become more
reactive as you go down the group. - Elements in group 7 become less reactive as
you go down the group.
