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Read this entire handout carefully before answening 1. Of all the known elements

ID: 1041571 • Letter: R

Question

Read this entire handout carefully before answening 1. Of all the known elements, natural and synthetic, how many are metals? How many are metalloids? How many are nonmetals? (Consult a periodic table to answer.) Ctri difference in their electron arrangement. Consider these four species. Determine the number of protons, neutrons and electrons in each. Then write the electron configuration of each. 2. Combined atoms and uncombined atoms behave differently. This is due to the In Su (uncombined) How sodi b Na(always part of a compound) (uncombined) C. 16 Wher prope (always part of a compound) 16 NTE ) oft und in this experiment or another book, complete and balance the ternal rgy nge i following equations. a. Mg + HCl(aq) ? The to 1 Br2 + KI(aq) ? nt c

Explanation / Answer

1.

At present there are 112 elements recognised by IUPAC.

Out of them 18 are non metals, 07 are metalloids and 87 are metals

2.

(a) 2311Na

No.of protons = no.of electrons = 11

No.of neutrons = 23 - 11 = 12

Na ( Z = 11 ) E.C is 1s2 2s2 2p6 3s1

(b)

2311Na+

No.of protons = 11

no.of electrons = 10

No.of neutrons = 23 - 11 = 12

Na ( Z = 11 ) E.C is 1s2 2s2 2p6

(c) 3316S

No.of protons = no.of electrons = 16

No.of neutrons = 33 - 16 = 17

S ( Z = 16 ) E.C is 1s2 2s2 2p6 3s2 3p4

(d)

3316S2-

No.of protons = 16

no.of electrons = 14

No.of neutrons = 33 - 16 = 17

S2- ( Z = 11 ) E.C is 1s2 2s2 2p6 3s2 3p2

3.

(a)

Mg (s) + 2 HCl (aq.) --------> MCl2 (aq.) + H2 (g)
(b)

K (s) + 2 H2O (l) ----------> 2KOH (aq.) + H2 (g)

(c)

Br2 (l) + 2 KI (aq.) --------> 2 KBr (aq.) + I2 (s)

(d)

MgO (s) + H2O (l) ---------> Mg(OH)2 (s)