Question

in this performance task, you will answer 4 questions.
the united nations declared the year 2019 as the year of the penodic table. the year 2019 marks 150 years since the discovery of the periodic system of the arrangement of elements which led to the periodic table, mostly credited to dmitri mendeleev. since 1869, scientists have discovered or synthesized a number of new elements which exhibit properties in keeping with the logic of the arrangement of elements in the penodic table. like mendeleev, scientists have been able to predict the atomic number, placement in the penodic table, and properties of elements that had not yet been discovered or synthesized.
in 2016, the international union of pure and applied chemistry (iupac) announced the discovery of four new elements with atomic number, name, and symbol as follows

• 113, nihonium, nh
• 115, moscovium, mc
• 117, tennessine, ts
• 118, oganesson, og

these new elements all occupy penod 7 of the table, with oganesson (og) being a noble gas
the fact that the four new elements are penod 7 of the table means that they all
o have seven shells of electrons
o have an effective nuclear charge of 7+
o have seven valence electrons
o form ions with charges of 7+

Explanation:

In the periodic table, the period number of an element corresponds to the number of electron shells it has. So, if an element is in Period 7, it has seven shells of electrons.

• The effective nuclear charge is not simply equal to the period number. It depends on the shielding effect and the number of protons.
• The number of valence electrons is related to the group number (for main - group elements). For example, noble gases (Group 18) have 8 valence electrons (except helium).
• The charge of ions formed is related to the group number and the tendency of the element to gain or lose electrons to achieve a stable electron configuration. It is not directly related to the period number.

Answer:

have seven shells of electrons