Question

Which of the following statements about the periodic table are correct? u.. elements are arrange in order of increasing atomic mass I. a period is horizontal row III. The properties of the elements within a period vary from element to element A. I and II B. I and III C. II and III D. I, II and III​

Answer 1

$\huge\bold\pink{answer}$

The periodic table of elements arranges all of the known chemical elements in an informative array. Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass. The rows are called periods.

Answer 2

1.Elements are arrange in order of increasing atomic mass

True

In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom. In a periodic table arranged in order of increasing atomic number, elements having similar chemical properties naturally line up in the same column.

2.A period is horizontal row

True

A period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one beginning at the far left.

3.The properties of the elements within a period vary from element to element

True

Chemical properites of an element is due to electrons persetn in the valecies shell .Elements of the same period passes different number of valene electrons hence their chemical properties vary along a period.

Hence,all options are correct.

Therefore,option D. i, ii and iii is the correct answer.