What is one key physical difference between transition metals and poor metals?

А. Atomic mass

B. Hardness

C. Reactivity

D. Charge

Order of filling levels and sublevels of electrons: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²3f¹⁴5d¹⁰6p⁶for an element with 5 electrons in the 3d energy level: full configuration: 1s²2s²2p⁶3s²3p³.

Bis is the

Answer is:     2,488 mol.chemical reaction: 2k +2hbr  → 2kbr + h₂.n(k) = 5,87mol.%product = 84,8% = 0,848.n(h₂) = ? n - amount od substance.n(k) : n(h₂) = 2 : 1.5,87 mol : n(h₂) = 2: 1.n(h₂) = 2,935 mol, if reaction is 100%.actual moles 0,848  · 2,935 mol = 2,488 mol.

Answer: option a.explanation.the question is incomplete. you should have shown the reaction on which x appears.any way, this question intends that you use the activity knowledge about the metals to predict which can replace x.1) then, you can approach the question by analizyng the activities of the four metallic elements shown in the choices; sr, al, sn, au.2) the activity series of the metals in the list of options, plus the hydrogen is:   sr > al > sn > h₂ > au.h₂ is included as a reference.3) from that series, you have: if the element replaced has more activity than al, only sr can replace it: these are some metals more active than aluminum but less active than sr: sr > ca > na > mg > be > al.and as the first series shows, al is more active than sn and au.then if the element fo be replaced is ca, na, mg or be, only sr is more active than al,  sn and au.from which, the answer is the option a.that has to be the answer, because any other metal would lead to an ambiguos answer.