Chemistry Flashcards
What is an atom?
An atom is the smallest subdivision of matter that retains the characteristics of the element.
It is composed of protons, neutrons and electrons connected with bonds.
Atoms are electrically neutral
What is an anion?
A negatively charged ion
What is a cation?
A positively charged ion
What is cohesion?
The electromagnetic forces of attraction existing between the atoms or ions of a substance, as a result they offer a resistance to separation
What is a compound?
Compound is a group of molecules formed by the combination of different elements.
What is a substance?
A substance is made of two or more kinds of atoms with different numbers of protons and different atomic numbers.
What is an electron?
A negatively charged particle that have virtually no mass.
Orbits around the nucleus in distinct shells (or energy levels).
What is an element?
Substances made up of only one kind of atom which cannot be split into simpler substances by chemical means, such as gold, copper, carbon (diamond) or combinations of elements which have certain fixed proportions called compounds such as corundum, spinel.
What is an ion?
An atom that is no-longer electrically neutral by either gaining electrons or losing electrons
What is ionic bonding?
Occurs between metallic and non-metallic Ions by electron transfer.
The ion loses or gains electrons to give a stable shell of outer electrons.
These are cations (positive) and anions (negative)
The charge is called valency.
Occurs between ions of opposite charge.
What is a molecule?
When atoms combined together they form a new entity called a molecule, which is the smallest particle of a substance, be it element or compound, which can exist in a free state.
Neutrons
Have no electrical charge (neutral)
Are contained within the nucleus
Protons
Have a positive (+) electrical charge.
Are contained within the nucleus.
The atomic number is the number of protons in the nucleus
What is a transition element? Name 5
A group of eight metallic elements with Atomic Numbers 22 to 29 which have variable valency; Ti, V, Cr, Mn, Fe, Co, Ni, Cu, U, N
What is valency?
The combining power of an ion, the number of electrons which the atom needs to lose or gain to obtain a stable outer shell
