Answer:
Elements having same valence electrons are placed in <u>same group.</u>
Explanation:
First, let's start with some basic concepts of modern periodic table:
1. Modern Periodic table : It is the arrangement of element in the increasing order of their atomic numbers
The Modern periodic table is divided into Periods and groups .
Periods : These are the horizontal rows. There are seven periods in the periodic table . Period 1 has 2 element. Period two and three has 8 elements , period 4 and 5 have 18 elements and the period 6 and 7 have 32 elements.
Same period have same number of atomic orbital(Shell)
Group : The group is the vertical columns . There are 18 groups in the modern periodic table.Those element which have same group number will also have same number of electron in their outermost shell. The number of electron in the outermost shell determines the valency of the element.
So, elements showing same valency are placed in same group.
All alkali are place in group 1 and have 1 valance electron in the outermost shell
Answer:
c.boron-11
Explanation:
The atomic mass of boron is 10.81 u.
And 10.81 u is a lot closer to 11u than it is to 10u, so there must be more of boron-11.
To convince you fully, we can also do a simple calculation to find the exact proportion of boron-11 using the following formula:
(10u)(x)+(11u)(1−x)100%=10.81u
Where u is the unit for atomic mass and x is the proportion of boron-10 out of the total boron abundance which is 100%.
Solving for x we get:
11u−ux=10.81u
0.19u=ux
x=0.19
1−x=0.81
And thus the abundance of boron-11 is roughly 81%.
Answer:
What is the name of the drug you were talking at the time of coming up with this theory please?
Answer:
Explanation:
The products of a chemical reaction have different properties than the reactant because they underwent a chemical change by definition of a chemical reaction. The products are new combinations atoms forming different molecules.
Answer:
a. equal to
Explanation:
The <em>osmotic pressure</em> is calculated by the formula:
π = <em>i</em> * M * R * T
Where π is the osmotic pressure, M is the concentration, R is a constant, T is temperature and <em>i</em> is the van't Hoff's factor (the number of ions a compound forms when dissolved in water,<u> for both NaCl and KBr is 2</u>).
Because R is always the same, and <u>Temperature and Concentration are equal between the two solutions</u>, the osmotic pressure of both solutions are also equal.
