Answer:
Check the electronic configuration of elements.
Explanation:
▪Valence electrons are the elwctrons present in the outermost shell of any element.
For example,
Electronic Configuration of Sodium = 2,8,1
Here , Sodium has 1 valence electrons.
▪Valency of an element is the total no. of electrons to be gained/losed in order to achieve duplet/octate state.
For example,
Electronic configuration of Sodium = 2,8,1
Sodium can achieve octate state either by losing 1 electron or gaining 7 electrons. But losing 1 electron is eay than gaining 7 electrons. So Valency of Sodium = +1
☆Metals have 1 or 2 or 3 valence electrons.
☆Non metals have 4 or 5 or 6 or 7 valence electrons.
☆Noble gases tend to stay in duplet/octate state i.e they have 2 or 8 valence electrons.
I think c is used in electric power plants.
Answer:
A solution is made by dissolving 4.87 g of potassium nitrate in water to a final volume of 86.4 mL solution. The weight/weight % or percent by mass of the solute is :
<u>2.67%</u>
Explanation:
Note : Look at the density of potassium nitrate in water if given in the question.
<u><em>You are calculating </em></u><u><em>weight /Volume</em></u><u><em> not weight/weight % or percent by mass of the solute</em></u>
Here the <u>weight/weight % or percent by mass</u> of the solute is asked : So first convert the<u> VOLUME OF SOLUTION into MASS</u>
Density of potassium nitrate in water KNO3 = 2.11 g/mL

Density = 2.11 g/mL
Volume of solution = 86.4 mL



Mass of Solute = 4.87 g
Mass of Solution = 183.2 g
w/w% of the solute =


w/w%=2.67%
Answer:
Like most other metals, Gallium is solid at room temperature (or liquid if it is too hot in your room). But, if it is held [in hands] for long enough, it melts in your hands, and doesn't poison you like Mercury would. This is because of its unusually low melting point of (~29 degree Centigrade).
- It melts once it reaches its melting point.
:)