In the modern wave mechanical model of the atom, the orbitals are regions of the most probable location of

  electrons
  positrons
  protons
  neutrons

which group of atomic models is listen in historical order from the earliest to most recent

  hard sphere model, wave mechanical model, electron shell model
  hard sphere model, electron shell model, wave mechanical model
  electron shell model, wave mechanical model, hard sphere model
  electron shell model, hard sphere model, wave mechanical model

The modern model of the atom shows that electrons are

  located in a solid sphere covering its nucleus
  combined with neutrons in the nucleus
  found in regions called orbitals
  orbiting the nucleus in fixe paths

Which particles are found in the nucleus of an atom

  e
  n
  p+n
  P+E

How do you find the number of neutrons

  p-e
  n+e
  m-e
  e+p

the atomic number of an atom is always equal to the number of its

  protons only
  neutron only
  protons plus neutron
  protons plus electrons

Which of these phrases best describes an atom

  a positive nucleus surrounded by a hard negative shell
  a positive nucleus surrounded by a cloud of negative charges
  a hard sphere with positive particles and are found in the nucleus
  tthey are hard sphere with negative particles uniformly embedded

What two parts of an tom have different masses and different charges

  P+n
  N+e
  orbitals + ions
  P+e

When an atom becomes a negative ion the radius

  decreases
  increases
  remains the same
  increases then egresses

As an atom becomes an ion, its mass number

  decreases
  increases
  remains the same
  increases then decreases

When an atom becomes a positive ion the radius

  decreases
  increases
  remains the same
  increases then decreases

As a atom becomses a negative ion the atom

  gains an electron and its radius increases
  gains an electron and its radius decreases
  oses an electron and its radius increases
  loses an electron and its radius decreases