It’s solved by using a pretty standard formula for efficiency.
Answer:
Option b. Effective nuclear charge increases as we move to the right across a row in the periodic table
Explanation:
The <em>effective nuclear charge </em>is a measure of how strong the protons in the nucleus of an atom attract the outermost electrons of such atom.
The <em>effective nuclear charge</em> is the net positive charge experienced by valence electrons and is calculated (as an approximation) by the equation: Zeff = Z – S, where Z is the atomic number and S is the number of shielding electrons.
The shielding electrons are those electrons in between the interesting electrons and the nucleus of the atom.
Since the shielding electrons are closer to the nucleus, they repel the outermost electrons and so cancel some of the attraction exerted by the positive charge of the nucleus, meaning that the outermost electrons feel less the efect of attraction of the protons. That is why in the equation of Zeff, the shielding electrons (S) subtract the total from the atomic number Z.
The <em>effective nuclear charge</em>, then, is responsible for some properties and trends in the periodic table. Here, you can see how this explains the trend of the atomic radius (size of the atom) accross a row in the periodic table.
- As the<em> effective nuclear charge</em> is larger, in a same row of the periodic table, the shielding effect is lower, the outermost electrons are more strongly attracted by the nucleus, and the size of the atoms decrease. That is why as we move to the right in the periodic table, the size of the atoms decrease.
The correct answer is A, 2x^3 - x^2 +3x +7
Answer:
A - elastic since many other fast food items could be considered close substitutes.
Explanation:
The price elasticity of demand is how much the demand of the Big Macs will change due to a 1% change in price. Should the elasticity be greater than 1, the Big Macs will be elastic. Should it be less than 1, the Big Macs are inelastic.
Demand elasticity is calculated as the percentage change in quantity demanded divided by a percentage change in price.
Since Big Macs are (i) a luxury good, and (ii) have close substitutes (other burgers available at McDonalds and other fast food stores), we will say their elasticity is greater than 1.
This means that the demand of Big Macs will change due to a 1% increase in price due to the presence of close substitutes.
