Question
HEM 03 0 0 1 How many sianifcant fngures tfoes thes result of the folowing operation ave? Spring 6 Exam sane What is it cailed when two or more stoms are joined together? ^)a meta, Bja mixture C) a solution Dha molecuile , tow many oiect, ons does " neutral atom or cobalt-50 have? A)0 ) 27 0)60 0) 32 4 How many unpaired ulectrons are there in the ground stato ot Age? s Which of the following is a property of ionic compounds? A) They have variable, and usuality low, melting points C) Their aqueous solutions are poor conductors of electricity D) They are always fiammable E) They exist as individual molecules Which of the following choices correctly represents the ionization of potassium? 0) K Which of the following correctly represents the formation of a chloride anion from chiorine atom? 8 What is the formula of the ionic compound formed from ions of aluminum and phosphorus? D)AIPE)AIP What is the formula of the ionic compound formed from ions of strontium a nitrogen?
Explanation / Answer
2) molecule
3) Ans = 27
atomic number of cobalt = 27
atomic number = total no of electrons (or) total no of protons
Hence,
no of electrons in neutral Cobalt-59 = 27
4) Ans = 1
Al = 13 = 1s2 2s2 2p6 3s2 3p1
One electron in 3p in unpaired.
Therefore, no of unpaired electrons in Al =1
5) Ans = B
Ionic compounds usually have high melting and boiling points.
6) Ans = B
Atomic number of K = 19
Electronic configuration of K= [Ar] 4s1
7) B
8) D
9) Sr3N2
