Question

Determina nr de electroni respectiv neutroni din:
a)23g sodiu
b)2moli potasiu
c)5kmoli neon
d)4kg calciu

Answer 1

a)     Na --->   Z=11    ,  A=23  -----> 11e  , 12 n

23 g Na------1mol Na--------11 . 6,023 .10 ²³ e ---------12. 6,023 .10²³ n

b) K---> Z=19 ,A=39  -------> 19 e , 20 n

 39 g K -------1mol K -------19 .6,023 .10²³ e ----------20 .6,023 .10²³ n

                   2moli K---------------X----------------------------Y

X=2. 19 .6,023 .10 ²³ e =

y= 2 .20 .6,023 .10²³ n =

c) Ne-----> Z=10 , A=20 -----> 10 e , 10 n            [  5kmoli=5000 moli ]

20 g Ne-------1mol Ne--------10 . 6,023 .10²³ e ---------10.6,023.10²³ n

                     5000moli Ne----------x-----------------------------y

x=5000. 10 . 6,023 .10²³ e  =

y=5ooo. 10 .6,023.10²³ n  =

d) Ca  Z=20 , A=40 -----> 20 e , 20 n           [ 4kg Ca= 4000 g ]

40 g Ca--------1mol Ca--------20 . 6,023 .10²³ e---------20 . 6,023 .10 ²³  n

4000g Ca --------xmoli-----------------ye--------------------------z n

x=4000 : 40=100 moli Ca

y=100 .20 .6,023 .10²³ e =

z=100 . 20 .6,023 .10 ²³ n =2.10³ . 6,023 .10²³ n

                                            =12,046 .10³ .10²³ =