Atomic Structure Unit Test Version 1 Part 2
Base your answers to questions 21 and 22 on the information below and on your knowledge of
chemistry.
The Bohr model of the atom was developed in the early part of the twentieth century. A
diagram of the Bohr model for one atom, in the ground state, of a specific element, is shown
below. The nucleus of this atom contains 4 protons and 5 neutrons.
21- An electron absorbs a packet of energy called quanta to go to a higher level or excited state.
In simple words, an electron has more energy at excited state than being at ground state.
When an electron is in excited state it is on a higher energy level, which simply means that an
electron is farther (at increased distance) from the nucleus.
22- The nucleus of the atom in question number 21 contains 4 protons and 5 neutrons. Therefore,
the element with atomic number 4 or 4 protons is Beryllium. Beryllium (Be) also has 4 electrons.
In the periodic table, right under the symbol of Be the written electronic configuration is 2, 2,
which means that the Be has 2 electrons in the first shell and 2 electrons in the second shell.
23- Hydrogen has three isotopes. Hydrogen-1 (Protium), Hydrogen-2 (Deuterium) and
Hydrogen-3 (Tritium).
Tritium has 2 neutrons and Protium has no neutron.
Base your answers to questions 24 through 27 on the table below.
24- the correct numerical setup for calculating the atomic mass of copper is
(62.930 u)(0.6917) + (64.928 u)(0.3083)
or
(62.930 u)(69.17) + (64.928 u)(30. 83)
100
100
25- The atomic mass of Cu-63 in the table above is 62.930 amu and it has 5 significant figures.
26- An atom of Cu-63 differ from Cu-65 in having 2 less or fewer neutrons than an atom of Cu-65. An atom
of Cu-63 has 34 neutrons and an atom of Cu-65 has 36 neutrons.
27- The total number of electrons in an atom of Cu-65 is 29 because copper has atomic number of 29, which
simply means that an atom of copper has 29 protons and 29 electrons.
Base your answers to questions 28 through 30 on the information and diagram below.
One model of the atom states that atoms are tiny particles composed of a uniform mixture of
positive and negative charges. Scientists conducted an experiment where alpha particles were
aimed at a thin layer of gold atoms.
Most of the alpha particles passed directly through the gold atoms. A few alpha particles were
deflected from their straight-line paths. An illustration of the experiment is shown below.
28- After Rutherford’s experiment Thompson’s plum-pudding model be revised to include that the atom
has a positively charged nucleus and negative electrons surround the outside.
29- the passing of most alpha particles directly through the gold foil provided evidence that the atom is
mostly empty space.
30- A few of the alpha particles were deflected by the positively charged nucleus {Alpha particles are
nucleus of the helium atom; 2 protons and 2 neutrons} Positive nucleus repelled the positives (protons)
in the alpha particles.
31- The Lewis electron dot diagram for a chlorine ion,
Cl-
is any one of the following.
32- The Lewis electron dot diagram for an atom of boron is one of the following.
33-
In terms of both electrons and energy state different colors of light are produced when electrons return
from higher energy state to lower energy state. Or
Light energy can be emitted when electrons in excited atoms return to lower shells. Or
Electrons release energy as they move towards the ground state.