SCC MODULE 1

what are the building blocks of matter

atoms

molecules

ions

describe atoms + example:

smallest particles of an element capable of existence

Carbon - C

Sodium - Na

describe molecules + example:

group of two or more atoms held together by chemical bonds;

O2, CO2

describe ions + examples

electrically charged atoms or groups of atoms

O²-

Na+

define element + types of elements:

pure substance that cannot be broken into other substances by chemical means

• metals

• molecular

• network

describe metals

pure metals contain billions of atoms, formulae is written as the symbol of the element

describe molecular elements & compounds

shows the number of atoms in one molecule O2, H2, CO2

formed from non-metals only

describe network elements & compounds

represented as the symbol of the element, diamond = C. ZnS, SiO2

formed from semi-metals and non-metals

name and describe the forms of carbon: C

1. graphite - black, brittle, soft and cheap

2. extremely hard, colourless, very high melting point and expensive

define compounds + examples:

pure substance made up of 2 or more elements in fixed proportions

• molecular

• network

• ionic

explain ionic compounds:

shows relative numbers of ions in the substance, contains a metal and non-metal

NaCl, CaCO3

what does the atomic number define

number of protons in nucleus

what does the mass number define:

mass of protons, neutrons in nucleus

how are the properties defined down a group, across a group

down a group, similar properties

across a row, properties differ

define mixtures and how they can be classified

2 or more substances mixed together which do not combine to form new substance and don’t need to be in fixed proportions

homogenous and heterogenous

define homogenous matter

uniform composition throughout

define solution

homogeneous matter that varies, physically separable into pure substances

define pure substances

fixed composition cannot be further purified

define heterogenous matter

non uniform composition throughout, which can be physically separable into homogenous matter

4 separation of mixture techniques:

filtration and crystallisation

distillation

chromatography

explain filtration and crystallisation

liquid and solid mixed together. separating a mixture into its pure substance

explain distillation

2 liquids dissolved in each other

explain chromatography

analytical technique for purification of mixture of compounds

describe a physical change

no new substance is produced; melting, boiling, dissolving

describe a chemical change

new substance is formed, atoms are conserved

describe a nuclear change

atoms are changed from one type to another; Hydrogen transformed to helium by fusion

distribution of top 3 elements in the body and their role:

oxygen -65% - cellular respiration, component of water

carbon - 18.5% - basis of organic molecules

hydrogen - 9.5% - component of water and most organic molecules, electron carrier

role of molybdenum in our body

• acts as a catalyst for chemical changes necessary in plants

• essential for useful deconstruction of sulphur containing amino acids

describe the nucleus of an atom

contains protons and neutrons

positive charge due to protons

describe the electrons in an atom

same number of protons and electrons

electrostatic attraction between nucleus and electrons

move through a relatively large volume of space

define nuclide symbols:

mass number above atomic number

explain atomic weight

average relative atomic masses of isotopes, % x isotope number + % x isotope number

what are trends in a periodic table

across a period, elements become increasingly non metallic

down a group, elements become increasingly metallic

within a group, elements have the same electron configuration and similar properties