Question

the united nations declared the year 2019 as the year of the periodic 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 periodic table. like mendeleev, scientists have been able to predict the atomic number, placement in the periodic 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 period 7 of the table, with oganesson (og) being a noble gas
which statements would be expected to be true for organesson? select all that apply
□ it has a high electron affinity
□ it has a full valence shell of electrons
□ it has the largest atomic radius of the four new elements
□ it has the lowest effective nuclear charge of the four new elements
□ it is relatively unreactive

Explanation:

• Electron affinity: Noble gases have low electron affinity as they have stable electron configurations. Oganesson is a noble gas, so it does not have a high electron affinity.
• Valence shell: Noble gases have a full valence shell of electrons (except helium which has 2 electrons in the first shell). Oganesson, being a noble gas, has a full valence shell.
• Atomic radius: In a period, atomic radius decreases from left to right. Among the four new elements (113 - 118), Oganesson (118) is on the far right. So it has the smallest atomic radius among them, not the largest.
• Effective nuclear charge: In a period, effective nuclear charge increases from left to right. Oganesson (118) has the highest effective nuclear charge among the four new elements, not the lowest.
• Reactivity: Noble gases are relatively unreactive due to their stable electron configurations. Oganesson, being a noble gas, is relatively unreactive.

Answer:

• It has a full valence shell of electrons
• It is relatively unreactive