Atomic Structure
•
• The nucleus is very small compared to the whole atom, but most of the mass of the atom
is concentrated in the nucleus; this means the nucleus is very dense.
• Electrons whizz around the nucleus in orbitals. The orbitals take up most of the volume of
the atom.
• Isotopes: atoms of the same element with the same numbers of protons and electrons but
different numbers of neutrons. (Eg: Cl-35 and Cl-37). Chemical properties depend on the
number of electrons in the outer shell, and since isotopes have the same number of
electrons, they have the same chemical properties. However, physical properties depend
on the mass of the atom, so isotopes have different physical properties.
, Models of the Atom
W
• Subshell: s, p, d, f
• Orbitals: Fr Fr Fr
• electrons occupy the lowest energy levels first (exception: chromium and copper)
• 4s has lower energy than 3d
• electrons occupy orbitals singly before sharing
•
• The nucleus is very small compared to the whole atom, but most of the mass of the atom
is concentrated in the nucleus; this means the nucleus is very dense.
• Electrons whizz around the nucleus in orbitals. The orbitals take up most of the volume of
the atom.
• Isotopes: atoms of the same element with the same numbers of protons and electrons but
different numbers of neutrons. (Eg: Cl-35 and Cl-37). Chemical properties depend on the
number of electrons in the outer shell, and since isotopes have the same number of
electrons, they have the same chemical properties. However, physical properties depend
on the mass of the atom, so isotopes have different physical properties.
, Models of the Atom
W
• Subshell: s, p, d, f
• Orbitals: Fr Fr Fr
• electrons occupy the lowest energy levels first (exception: chromium and copper)
• 4s has lower energy than 3d
• electrons occupy orbitals singly before sharing
