ASB (atomic structure and bonding) Flashcards
define matter
Anything with mass that takes up volume(solid liquid gases etc)
relative masses, charges and locations of P, N and E
Relative masses: p = 1, n = 1, e = 0
Relative charges: p = +1, n = 0, e = -1
Location:
p in nucleus
n in nucleus
e orbiting in shells
what is atomic number and mass number
atomic number (z)= number of protons
mass number (A)= proton number + nuetron
define relative atomic mass (Ar)
the number of times heavier an average atom is than one-twelfth of a carbon-12 atom - taking into account the different isotopic masses and their relative abundance
equation for Ar
Relative Atomic Mass = (mass x % abundance) + (mass 2 x % abundance) / 100
define ion
a positively or negatively charged atom, or covalently bonded group of atoms
define isotopes - how are they different/same
Atoms with the same atomic number but different mass number/ the same number of protons but a different number of neutrons”
- reactivity is the same but physical properties are slightly different
define ionic bonding
occurs between a metal and non-metal atom, atoms lose or gain electrons to complete a shell
define covalent bonding
occurs between two non-metal atoms, electrons are shared to complete a full shell
define metallic bond
electrostatic attraction that exists between the positively charged cations and the sea of delocalised electrons, occurs between metals,
describe cations and anions
Cations- positive (cats have paws), losing electrons, metal ions
Anions- negative, gaining electrons, non metal ions
name molecular ions and their symbols
Ammonium- NH₄⁺
Hydroxide OH¯
carbonate CO₃²⁻
phosphate PO₄³⁻
Nitrate NO₃-
Sulfate SO₄²-
factors that affect force of attraction:
- strength of bond (smaller = stronger)
- charge of the iron (higher = stronger)
^ Together they’re called charge density
what are the 3 rules of octet and the exceptions
Rule of Octet
- Stability- Atoms are most stable when their outermost energy level is full
- ionic Bonding: Atoms may gain or lose electrons to achieve a full octet.
- Covalent Bonding:Atoms may also share electrons through covalent bonding to achieve a full octet.
Exceptions:
While the rule of octet applies to many molecules and ions, there are exceptions. Some atoms, particularly those in the second period (e.g., boron, beryllium, and hydrogen), may form stable molecules with fewer than eight electrons in their outer shell
Dative Bond
when both electrons are provided by the same atom (lone pair)
why do atoms form compounds
to become stable and gain a full outer shell (noble gas formation)
define valecy
- number of other atoms that an atom of an element can combine with depends on the number of electrons it can lose, gain or share
- i.e. the number of electrons in its outer shell
which elements dont normally form ionic compounds becuase of the large amount of energy required
C, Si, Be and B
complete the acid reactions-
- Acid + Alkali >
- Acid + Base >
- Acid + Carbonate >
- Acid + Metal >
- Salt + Water
- Salt + Water
- Salt + Water + Carbon dioxide
- Salt + Hydrogen
what is avogadros constant (mole)
6.022 × 10²³
what is the difference between Relative Molecular mass (Mr) and Relative Formula Mass (RFM)
Mr, of a compound is relative to C-12 and RFM is the AVERAGE mass of the formula of an ionic compound relative to C-12
How do you work out Mr and RFM
Add up all the Ar’s present,
e.g. RFM of NaOH = 23+ 16 + 1 = 40
formula to work out number of moles
Number of moles = mass (in grams) / Molar Mass (Ar, Mr, RFM)
Difference between Empirical Formula and Molecular formula
EF is the simplest whole-number ratio of elements present in a compound while MF is the actual whole-number ratio of elements present in a compound