51.

What are the terms defined in given below?

i) A bond formed by a shared pair of electrons, each bonding atom contributing one electron to the pair.

ii) A bond formed by a shared pair of electrons with both electrons coming from the same atom.

The following questions refer to the periodic table:

i) Name the first and last element in period 2.

ii) What happens to the atomic size of elements moving from top to bottom of  the group?

iii)Which of the elements has the greatest electron affinity among the halogens?:- 

Iv)What of the common features of the electronic configuration of the elements in group 7?

i) The metals of group 2 from top to bottom are : Be, Mg,Ca,Sr,Ba. Which of these metals will form ions most readily and why?

ii) What property of an element is measured by electronegativity?

The equation for the burning of octane:

2C₈H₁₈ +25O₂----> 16CO₂ +18H₂O

i) How many moles of carbon dioxide are produced when one mole of octane burns?

ii) What volume, at STP, is occupied by the number of moles determined in  ?

iii) If the relative molecular mass of carbon dioxide is 44, what is the mass of carbon dioxide produced y burning two moles of octane?

iv) What is the empirical formula of octane?

i) A compound has the following percentage composition by mass carbon 14.4% hydrogen 1.2% and chlorine 84.5%. Determine  the empirical this compound. Work correct to 1 decimal place ( H=1;C=12;Cl=35.5)

ii) The relative molecular mass of this compound is 168, so what is its molecular formula?

iii)by what type of reaction could this compound be obtained from ethyne ?