Chemistry, 15.07.2019 15:20 unicornsflyhigh

Element a has seven valence electrons. how does its reactivity compare to that of element b, which has four valence electrons?

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Answer from: serianmollel

The correct answer is "Element A is more reactive".

Explanation:

The missing options of this question are:

Element A is more reactive.

Element A is less reactive.

Element A and B have the same reactivity.

Element A has no reactivity.

The correct answer is "Element A is more reactive".

Valence electrons are defined as outer shell electron that can participate in the formation of chemical bonds with other atoms. The atoms tend to have either 0 or 8 valence electrons. Therefore, depending in the number of valence electrons, an atom can either give their valence electrons (1 to 3 electrons) or try to take more valence electrons (4 to 7 electrons). Element A with 7 valence electrons is more reactive that Element B with 4 valence electrons, because Element A only needs 1 more electron to full its 8 valence electrons.

Answer from: Quest

i can ! i just need to know what the paragraph is! : p

Answer from: Quest

assuming that your periodic table has eighteen columns, you should highlight the four elements in the third column from the left of the table.

explanation

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the $3d$ have energy higher than those in the $4 s$ orbital while lower than those of the $4 p$ orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the $4s$ orbital is therefore filled right after $3p$ orbitals and before $3 d$ orbitals.

potassium has electron configuration $[\text{ar}] 4 s^{1}$ and calcium $[\text{ar}] 4 s^{2}$ . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration $[\text{ar}] 4 s^{2} \; 3d^{1}$ and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the $ns^{2} \; (n-1) p^{1}$ and should be highlighted as well.

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Element a has seven valence electrons. how does its reactivity compare to that of element b, which h...