Section 2 Flashcards
How are elements in the periodic table arranged?
In order of increasing atomic number
Why do elements in the same group have similar chemical properties?
Their atoms have the same number of electrons in their outer energy level
What is the name of group 1, 7 and 8?
1- alkali metals
7- halogens
8- noble gases
How are metals made up?
They have very few electrons in their outer shell
How are the electrons in the outer energy level of metals described?
Delocalised, able to move from atom to atom quite easily
What holds metal atoms together?
Electrostatic attraction between the positive metal jobs and the negative delocalised electrons
How do you describe the structure of metals?
A giant lattice of metal ions with delocalised electrons between them
Which of the first 20 elements have metallic bonding and structure?
Lithium, beryllium, sodium, magnesium, aluminium, potassium and calcium
What is a monatomic element?
A single atom held together by london dispersion forces
What holds together monatomic elements?
London dispersion forces
Which group is the monatomic elements?
Group VIII-noble gases
What is a covalent molecular element?
A molecule (atom held together by covalent bonds)
How are the covalent molecules themselves held together?
London dispersion forces
What are examples of covalent molecular elements?
Diatomic elements, phosphorus, sulphur, and fullerenes
What are covalent network elements?
The exist as a giant network of atoms held together by covalent bonds
How are the atoms in a covalent network arranged?
A regular repeating three-dimensional pattern
What are examples of covalent networks?
Silicon, boron,
Carbon exists as a diamond and graphite
What is covalent radius?
A method of indicating the size of an atom found by taking half of the distance between the two nucleii
How does the atomic size suffered across a period?
Decreases
Each subsequent atom has the same number of energy levels but one extra proton so the larger nuclear charge attracts the outermost electrons more strongly pulling them closer to the nucleus
How does atomic size differ down a group?
Increases
Each subsequent atom has one additional energy level of electrons making the atom bigger
What is the first ionisation energy?
The energy required to remove one mole of electrons from one more of gaseous atoms
What is the second ionisation energy?
The energy required to remove one mole of electrons from one mole of gaseous 1+ ions
How does the ionisation energy differ across a period?
Increases
Each subsequent atom/ion has one addition proton so larger nuclear charge which attracts the outermost electron more strongly meaning more energy is required to remove this outermost electron
How does the ionisation energy differ down a group?
Decreases
Each subsequent atom has one additional energy level of electrons so the outermost electrons are further away from the nucleus and screened from the nuclear charge and are being less strongly attracted to the nucleus.
What is electronegativity?
The strength of the attraction of an atom involved in a covalent bind has for the shared pair of electrons in the bond
What is the most electronegative element?
Fluorine
How does electronegativity differ across a period?
Increases
Each subsequent atom has a greater nuclear charge so attracts the shared pair of electrons more strongly
How does electronegativity differ down a group?
Decreases
Each subsequent atom has one more energy level of electron so the shared pair of electrons in the bond are further from the nucleus and more screen from the nuclear charge so are less strongly attracted to the nucleus
