<span>If you match the physical properties of a substance you dont know about to the properties of a known substance, you now know what you've got. For example, if you know that compound X is bright yellow and screams when you poke it, an unknown sample that is yellow and screams that you poke it is probably compound X. trust me, im a dog in a suit.</span>
Numeric Keypad is the answer
According to the given question, sales is a two-dimensional array and contains 10 rows and 7 columns wherein each component is of type integer and the variables sum and j are also of integer type.
<u>Explanation:</u>
In order to find the sum of the elements of the fifth row of sales, the correct piece of code should be:
sum=0;
for(j=0;j<7;j++)
sum=sum+sales[4][j];
The indexing in an array always starts from zero, therefore, to calculate the sum of the fifth row, the user has to write 4 in the index to point to the fifth row.
Answer: This element needs 3 electrons to complete its octet state
Why?:
since the electrons in 2s2 are already paired they cannot form a bond pair with electrons from other elements without hybridisation however the 3 electrons in 2p3 are unpaired so can form bond pairs with electrons from other elements without hybridisation.
Hope this helps!