2. Atom structure - nucleus and electrons

Question 1

Describe the atomic orbital model (electron cloud)

Answer 1

Electron cloud is representation of electrons around the nuclei, and gives a picture of where it is likely to be. Atomic orbital are:
s, p, and d sub-levels, they can be used to explain and predict the chemical bonds that atoms can form.
s sub-level = is a spherical form, the 2s e- are further from the nucleus than electrons in 1s orbitals and are at higher energy.
p sub-level = contains 3p orbitals (3 rooms, carry 6 electrons) of equal energy, they have dumbbell shape; the only difference is their orientation ins space.
d sub-level = is made up of 5d atomic orbitals (5 rooms, carry 10 electrons)

Question 2

order of orbital (s, p, and d) and shell (K, L, M) occupation

Answer 2

Electron shells are labels as K,L and M. Electrons in outer shells have higher average energy and travel farther from the nucleus than those in inner shells. This makes them more important in determining how the atom reacts chemically and behaves as a conductor. In this way, a given element’s reactivity is highly dependent upon its electronic configuration.
Each shell is composed of one or more subshells, which are they composed of atomic orbitals. For example, the first (K) shell has one subshell, called 1s; the second (L) shell has two subshells, called 2s and 2p; the third shell has 3s, 3p, and 3d; the fourth shell has 4s, 4p, 4d and 4f;

Question 3

Describe the basic configurations of valence electrons

Answer 3

A valence electron can only be in the outermost electron shell, in a transition metal, a valence electron can also be in an inner shell. An atom with a closed shell of valence electrons (corresponding to an electron configuration s2p6) tends to be chemically inert. Atoms that need to gain more electrons to complete its valence shell tend to be negatively charged ions (s2p4), and those that need to lose electrons to complete its valence shell tend to be positively charged ions (s2p6s1).