Periodic Table Properties and Electron Configurations
A repetition of properties occurs when elements are arranged in order of increasing atomic number.
periodic law
type of element characterized by the presence of electrons in the d orbital
transition metal
basis for Mendeleev’s arrangement of the periodic table
atomic mass
subatomic particles that are transferred to form positive and negative ions
electrons
Each period in the periodic table corresponds to a(n)
principal energy level |
The modern periodic table is arranged in order of increasing atomic ____.
number
Who arranged the elements according to atomic mass and used the arrangement to predict the properties of missing elements?
Mendeleev
Which of the following categories includes the majority of the elements?
metals
Of the elements Pt, V, Li, and Kr, which is a nonmetal?
Kr
To what category of elements does an element belong if it is a poor conductor of electricity? ____
nonmetals
In which of the following sets is the symbol of the element, the number of protons, and the number of electrons given correctly?
In, 49 protons, 49 electrons |
The atomic number of an element is the total number of which particles in the nucleus?
protons
Elements that are characterized by the filling of p orbitals are classified as ____.
groups 3A through 8A |
Which of the following electron configurations is most likely to result in an element that is relatively inactive?
a filled highest occupied principal energy level |
Which of the following elements is a transition metal?
copper
Which of the following groupings contains only representative elements?
Al, Mg, Li |
Which of the following is true about the electron configurations of the representative elements?
The highest occupied s and p sublevels are partially filled. |
What are the Group 1A and Group 7A elements examples of?
representative elements |
Of the elements Fe, Hg, U, and Te, which is a representative element?
Te |
What is the charge of a cation?
a positive charge |
Which of the following statements is true about ions?
Cations form when an atom loses electrons. |
The metals in Groups 1A, 2A, and 3A
lose electrons when they form ions. |
Which of the following statements is true about ions?
When an anion forms, more electrons are transferred to it. |
By 1700, how many elements had scientists discovered and isolated?
13 |
By the early 1800’s, chemists started organizing elements into groups because
there were so many new elements that had been discovered. |
What is the name for the Group 2A elements?
alkaline earth metals
About what percent of elements is classified as metals?
80%
The s and p sublevels of an atom of an element in period 3 are filled with electrons. Which orbitals are filled in this atom?
1s 2s 2p
From which orbital in a lithium atom is an electron transferred to form Li
?
2s
What orbital is filled when iodine gains an electron to become a negative ion?
5p
How many electrons are there in the highest occupied energy level of atoms in Group 5A elements?
5
How many electrons are in a rubidium ion (Rb
)?
36
In 1829, the German chemist J. R. Dobereiner published a classification system in which elements were put into groups according to their properties. How many elements did he put in each of his groups?
3
How many electrons does the ion Ca
contain?
18
Explain how ions form. Provide examples.
Ions form when electrons are transferred among atoms. For example, a group 1A element, such as potassium, tends to transfer one electron to other atoms, causing it to form a net positive charge, in this case K
. Such ions with net positive charges are called cations. Ions with net negative charges are anions. Nonmetal atoms, such as chlorine, tend to accept electrons from other atoms. Chlorine tends to gain a single electron, forming the anion Cl
.
Describe the shapes and relative energies of the s, p, d, and f atomic orbitals.
S= sphere shape, lowest energy ; P= dumbbell shape, higher energy ; D= more complex shape, higher energy than s and p ; f= very complex shape highest energy
Describe the different principles that govern the building of an electron configuration.
The aufbau principle states that electrons enter the orbitals of lowest energy first. The Pauli exclusion principle states that each orbital can hold only two electrons. Hund’s rule states that electrons first enter separate orbitals of the same energy, with each electron having the same spin, before pairing with electrons that have opposite spins.
Explain what is meant by the Heisenberg uncertainty principle.
The measurement of the speed or position of a moving particle necessarily involves an interaction with the particle. Therefore, the position or the speed of the particle is changed as a result of the measurement. As a consequence, accurate measurements of both these variables cannot be made at the same time.
Explain why the 4s sublevel fills before the 3d sublevel begins to fill as electrons are added.
Electrons occupy orbitals in a definite sequence, filling orbitals with lower energies first. Generally, orbitals in a lower energy level have lower energies than those in a higher energy level. But, in the third level the energy ranges of the principal energy levels begin to overlap. As a result, the 4s sublevel is lower in energy than the 3d sublevel, so it fills first.