Answer:
Moving Across a Period
Moving from left to right across a period, the atomic radius decreases. The nucleus of the atom gains protons moving from left to right, increasing the positive charge of the nucleus and increasing the attractive force of the nucleus upon the electrons
Answer:
The correct answer is option C
Explanation:
According to Heisenberg's principle "At the instant of time when the position is determined, that is, at the instant when the photon is scattered by the electron, the electron undergoes a discontinuous change in momentum. This change is the greater the smaller the wavelength of the light employed, i.e., the more exact the determination of the position. At the instant at which the position of the electron is known, its momentum therefore can be known only up to magnitudes which correspond to that discontinuous change; thus, the more precisely the position is determined, the less precisely the momentum is known".
Hence, this principle made scientists to realize that electrons could not be located in defined orbits which a contradictory of Bohr's model.
Best Answer: Ionic binary compounds -- contain a metal cation and an anion made of a nonmetal or a polyatomic anion. Consider calcium phosphate:
Ca = 2+ (Group IIA)
PO4 = 3- (phosphate)
The lowest common multiple of 2+ and 3- is 6. You must have 3 Ca2+ to make +6; you must have 2 PO43- to make -6. The sum of the positive and negative charges must be equal in a compound because they are electrically neutral.
Ca3(PO4)2 -- calcium phosphate
Binary molecular compounds -- contain two or more nonmetals bonded covalently. There are no ions present because the atoms share electrons. Prefixes are used to indicate the number of atoms of each kind present. Examples are:
SO2 -- sulfur dioxide
N2O4 -- dinitrogen tetraoxide
PCl3 -- phosphorous trichloride
CO -- carbon monoxide
The general formula for an acid is HX, where X is an anion. Binary acids contain H and a nonmetal and are named with the prefix "hydro" and the suffix "ic". Examples are:
HCl -- hydrochloric acid
H2S -- hydrosulfuric acid
HF -- hydrofluoric acid
Ternary acids contain H and a polyatomic anion. Examples are:
H2SO4 -- sulfuric acid
HNO3 -- nitric acid
HNO2 -- nitrous acid
HClO3 -- chloric acid
HClO2 -- chlorous acid
HClO -- hypochlorous acid
The names of the anions are changed as follows:
-ate anions form -ic acids
-ite anions form -ous acids
per...ate anions form per...ic acids
hypo...ite anions form hypo...ous acids.
Answer:
ΔHrxn = - 1534.3 J
Explanation:
Given the assumptions and the formula for the change in enthalpy:
ΔHrxn = m x C x ΔT, where
m is the mass of solution given 135.4 g
C is the heat capacity 4.2 J/g .K and,
ΔT is the change in temperature
we have ,
T₁ = ( 18.1 + 273) K = 291.1 K
T₂ = ( 15.4 +273) K = 288.4 K
ΔHrxn = 135.3 g x 4.2 J/gK x ( 288.4 -291.1 ) K = - 1534.3 J
After verifying our result has the correct unit, the answer is -1534.3 Joules, and the negative sign tells us it is an endothermic reaction decreasing the final temperature.
