OCR Chemistry A-Level - Modules 1-4 (A+ GRADED)

what is water of crystallisation? correct answers water molecules that make up part of the crystal structure of a solid define relative isotopic mass correct answers the ass of an atom of an isotope of an element relative to one twelfth the mass of an atom of C-12 why is relative atomic mass written as a decimal? correct answers it is a weighted average mass define molecular formula correct answers the actual number of atoms of each element in a compound define what an orbital is correct answers a region within an atom that can hold up to two electrons of opposite spins what shape are S orbitals? correct answers spherical what shape are orbitals? correct answers figure of 8 how can you make out the electron structure of an element using the periodic table? correct answers period = energy level columns = electrons group = subshell show the oxidation of sodium and the reduction of chlorine correct answers Na - Na+ + e- Cl + e- - Cl- ions always go on the RHS whether oxidation or reduction define ionic bond correct answers the electrostatic force of attraction between positive and negative ions ionic bonding occurs between metals and non-metals but which ion is the exception? correct answers NH4+ define covalent bond correct answers the strong electrostatic force of attraction between the shared pair of electrons and the nuclei of the bonded atoms when non-metals covalently bond, what is their aim? correct answers the octet rule: - to reach a noble gas configuration (8 electrons in the outer shell) what are there exceptions to the octet rule? correct answers - NO (odd number of electrons) - BF3 (boron has less than 8 outershell electrons) - SF6 (sulfur has more than 8 outershell electrons)