Baìi 1:( 2 âiãøm )

Hai phi kim coìn laûi coï trong B^- phaíi coï säú proton tæång æïng Z vaì Z+1

Coï 3 træåìng håüp

TH1: M coï 2 nguyãn tæí H

Hoàûc 2 + 3Z +4Z(Z+1) =42 Z=36/7 (loaûi)

Hoàûc : 2 + 4Z +3(Z+1) = 42 Z= 36/7 (loaûi)

TH2: M coï 3 nguyãn tæí H

Hoàûc : 3 + 2Z + 4(Z+1) = 42 Z=35/6 (loaûi)

Hoàûc : 3 + 4Z + 2(Z+1) = 42 Z= 37/6 (loaûi)

TH3: M coï 4 nguyãn tæí H

Hoàûc : 4 + 2Z + 3(Z+1) = 42 Z=7 ( Nitå) (Z+1) = 8 ( Oxi)

CTPT cuía M : H₄N₂O₃ hay NH₄NO₃

Hoàûc 4 + 3Z + 2(Z+1) = 42 Z= 36/5 (loaûi)

b. cäng thæïc electron cuía M

H O

H N H O N

Cäng thæïc cáúu taûo

+ ­_

H O

H O