Answer:
- <u>Tellurium (Te) and iodine (I) are two elements </u><em><u>next to each other that have decreasing atomic masses.</u></em>
Explanation:
The <em>atomic mass</em> of tellurium (Te) is 127.60 g/mol and the atomic mass of iodine (I) is 126.904 g/mol; so, in spite of iodine being to the right of tellurium in the periodic table (because the atomic number of iodine is bigger than the atomic number of tellurium), the atomic mass of iodine is less than the atomic mass of tellurium.
The elements are arranged in increasing order of atomic number in the periodic table.
The atomic number is equal to the number of protons and the mass number is the sum of the protons and neutrons.
The mass number, except for the mass defect, represents the atomic mass of a particular isotope. But the atomic mass of an element is the weighted average of the atomic masses of the different natural isotopes of the element.
Normally, as the atomic number increases, you find that the atomic mass increases, so most of the elements in the periodic table, which as said are arranged in icreasing atomic number order, match with increasing atomic masses. But the relative isotope abundaces of the elements can change that.
It is the case that the most common isotopes of tellurium have atomic masses 128 amu and 130 amu, whilst most common isotopes of iodine have an atomic mass 127 amu. As result, tellurium has an average atomic mass of 127.60 g/mol whilst iodine has an average atomic mass of 126.904 g/mol.
The reaction is an exothermic one because heat is released to the surroundings. An exothermic reaction is a chemical reaction where energy is being released as the reaction by light or heat. On the other hand, endothermic reaction needs energy input for the reaction to proceed.
Answer:
Because: The mixtures contain unwanted substances which may be harmful and may degrade the properties of mixtures. So we, need to separated them and extract useful substances.
Answer:
Explanation:
Molar mass of KF= 39 + 19= 58g/mol
Mass of KF = 109g
Amount = mass/molar mass
Amount = 109/58
Amount = 1.9moles
A decade is 10 years. Therefore you must first multiply ten by five to get 50. After you multiply the 12 months in a year by the 50 years. Your answer should be 600
