E.oummer 18 rse Home Chemistry Primer-Semester 1 Understanding Chemical Symbols

ID: 303862 • Letter: E

Question

E.oummer 18 rse Home Chemistry Primer-Semester 1 Understanding Chemical Symbols K12 of2 the format for written symbols In the following table each column represents a neutral atom. Fill in the gaps in the following table by working this problem out on a separate sheet of paper. You will ned the periodic table in the "resources" drop down menu in the upper right hand corner of this question to look up atomic numbers and masses 79 26 50 30 64 48 86 Mass no. 222 119 Use the hints in the following part whenever needed to review the steps to filling in this type of table. Part A Once you have filled in all the gaps on a separate sheet of paper, enter the four missing element symbols in the first row of the table into the answer box below You can open the first hint to view a video that steps you through filling in the first column of the table Enter the four missing symbols for the first row of the table from left to right, separated by commas, into the answer box below /subscripts button (available in the templates button menu above the answer entry box) to enter the symbols in the folowing form atomic aunber Symbol, or for example, 33CI 9:20 PM

Explanation / Answer

Hint:

For find symbol of elements and atomic mass and number, first we should know:

Number of electrons = number of protons = atomic number

Number of neutrons + number of protons = atomic mass

Thus we can be solved this problem which given in table above

Solved answer in given table:

Symbol

79Br 35

56 Fe26

112Cd48

222 Rn 86

119 Sn 50

Protons

neutrons

136

electrons

mass No.

112

222

119

Given neutrons 30 and protons 26, it means atomic number is 26 and mass = 30 + 26 = 56

And electronic conf.: 2, 8, 8, 8 [ 4th period and 8th group, d-block element]

For 26: 3d6 4s2

* As in 4nd column:

Given electrons 86 and mass number: 222, it means atomic number is 86 and neutrons = 222- 86 = 136

And electronic conf.: 2, 8, 8, 18, 18, 32 [ 6th period and 8th A group, 0-group, noble gas element]

For 86: 6s 2 6P6