" <em>Energy is never created or destroyed.</em> "
All the rest is commentary.
Alkali metals: left column of your periodic table (not hydrogen, but anything below it). They have one valence electron, which they are happy to share in a reaction.
Halogens: second column from the right of your periodic table. They are one electron short of a full shell, so they are reactive in the opposite way that alkalis are--they want electrons.
Atomic number (number of protons) is the big number on the periodic table square. Hydrogen's is 1.
Atomic mass is a little number down below. For example, Hydrogen's is 1.008.
Neutrons are a tricky subject, because different isotopes of the same element can have different numbers of neutrons. You can't generally get this from the atomic mass, because the atomic mass is a weighted average of naturally occurring isotopes. Hydrogen can have 0,1, or 2 neutrons. To answer this, you'd have to choose a particular isotope from the table of isotopes (a completely different chart from the periodic table) which has a certain number of neutrons: n = weight - Z.
Valence electrons are the electrons in the outermost shell. (The column of the table).
<span>
Number of principal shells is the row of the periodic table. </span>
Answer:
density is defined as the amount of mass contained in unit volume of a body .its si unit is kg/m*3
Explanation:
Reactants ⇒ product + heat (exothermic reaction) ....(1)
We have given that the reaction is exothermic, so the heat is rejected from the reaction. We know that heat is the form of energy.
From equation (1)
from the given equation we can see that reactants have more energy than products.
So the reactants have higher potential energy in comparison to the products.
Answer:
a) 
b) 
c) 
d) 
Explanation:
<u>Given equation of pressure variation:</u>
![\Delta P= (1.78\ Pa)\ sin\ [(0.888\ m^{-1})x-(500\ s^{-1})t]](https://tex.z-dn.net/?f=%5CDelta%20P%3D%20%281.78%5C%20Pa%29%5C%20sin%5C%20%5B%280.888%5C%20m%5E%7B-1%7D%29x-%28500%5C%20s%5E%7B-1%7D%29t%5D)
We have the standard equation of periodic oscillations:
<em>By comparing, we deduce:</em>
(a)
amplitude:
(b)
angular frequency:
∴Frequency of oscillations:
(c)
wavelength is given by:
(d)
Speed of the wave is gives by:
