U1-2 - Atomic Bonding and Structure Flashcards
Column in the periodic table
Group
Row in the periodic table
Period
Name of group 1 in the periodic table
Alkali metals
Name of group 7 in the period table
Halogens
Name of group 0/8 in the periodic table
Noble gases
List the diatomic elements (there are 7)
H2 N2 O2 F2 Cl2 Br2 I2
How can you remember which elements are diatomic?
If their names end in ‘gen’ or ‘ine’, they are diatomic. Remember: genuine.
(e.g. oxygen)
A proton has a mass of ….. and a charge of …. .
mass = 1
charge = +1
A neutron has a mass of …. and a charge of …. .
mass = 1
charge = 0
An electron has a mass of …. and a charge of …. .
mass = 0
charge = –1
Protons and neutrons are located in the …
nucleus.
Electrons are located in …
electron shells.
Atomic number
The number of protons. Defines an element.
Mass number
The number of protons and neutrons
How do you calculate the number of neutrons in an atom?
No. of neutrons = Mass number – Atomic number
Why are atoms neutral?
Equal number of protons and electrons.
+ and – charges cancel out.
In the nuclide notation shown, 17 is the …
Atomic number
In the nuclide notation shown, 35 is the …
Mass number
How many electrons can fit in this shell?
2
How many electrons can fit in this shell?
8
What is a valence electron?
An electron in the outermost electron shell (furthest from the nucleus).
This question is about electrons
All elements in the same group have the same no. of …..
valence electrons.
(e.g. all group 1 elements have 1 valence electron)
This question is about electrons
All elements in the same period have the same no. of …..
occupied electron shells.
(e.g. all period 3 elements have 3 occupied shells)
Ion
A charged atom formed when an atom has gained or lost electrons
Why do atoms form ions?
To gain a full outer shell of electrons.
This makes them more stable.
Ions have the same electron arrangement as the nearest ….
Noble gas
What is wrong with the charge shown?
Zn+2
Number must be written first, then sign:
Zn2+
What is wrong with the charge shown?
3–N
Charge must be on the right:
N3–
Explain why noble gases do not form ions.
They already have a full outer shell.
The number of protons. Defines an element.
Atomic number
Are metal ions positive or negative?
Positive
Are non-metal ions positive or negative?
Negative
The number of protons and neutrons
Mass number
A charged atom formed when an atom has gained or lost electrons
Ion
State the structure of noble gases.
Monatomic (exist as single atoms).
Valency
The no. of bonds an atom can make
What is the valency of elements in groups 1–4?
1, 2, 3, 4 – same as the group number
(e.g. Ca is in group 2, valency = 2)
What is the valency of elements in groups 5–8?
3, 2, 1, 0 – same as the no. of electrons needed to get a full outer shell
(e.g. Cl is in group 7, valency = 1)
What does the (III) mean in iron(III) oxide?
Valency of iron is 3
(III = roman numeral 3)
The valencies of two elements are shown.
Fe N
2 3
What do you do to get the formula for a compound of Fe and N?
We must cross over the valencies:
Fe3N2
The valencies of two elements were crossed over, giving the following formula:
Mn2O4
What must be done next?
We must simplify the formula (to the simplest whole number ratio, so 2 : 4 = 1 : 2)
MnO2
The charge number of an ion is equal to the element’s …
valency.
(e.g. O has valency 2, and charge 2–)
Formula mass
The sum of all the masses of all the atoms present.
E.g. H2O: 2 x 1 + 1 x 16 = 18
Ionic bonds form between …
metals and non-metals.
(e.g. NaCl)
Covalent bonds form between …
non-metal atoms.
(e.g. CO)
Ionic bond
The electrostatic attraction between positive and negative ions.
Covalent bond
The attraction two positive nuclei have for a shared pair of e−.
Draw a diagram, showing all outer electrons, to represent a molecule of ammonia, NH3.
Low melting point:
covalent or ionic?
Covalent
Very high melting point:
covalent or ionic?
Ionic
Structure of an ionic solid
Ionic lattice
Type of bond formed between two non-metals
Covalent
Type of bond formed between a metal an a non-metal
Ionic
Conducts electricity:
covalent or ionic?
Ionic
When can an ionic compound conduct electricity?
When molten or dissolved.
The electrostatic attraction between positive and negative ions.
An ionic bond
There are two compounds, one ionic and one covalent.
How can you test them to find out which is which?
Conductivity test:
Does not conduct at all = covalent
Conducts when molten or dissolved = ionic
