Explanation:
An atom consists of two regions. The first is the tiny atomic nucleus, which is in the center of the atom and contains positively charged particles called protons and neutral, uncharged, particles called neutrons. ... Most atoms contain all three of these types of subatomic particles—protons, electrons, and neutrons.
Answer:
0.7824 KJ
Explanation:
Given data:
Mass of iodine = 25.4 g
Amount of heat required to melt = ?
Solution:
The heat of fusion of iodine is 7.824 Kj /mol
Number of moles of iodine = 25.4 g/ 254 g/mol
Number of moles of iodine = 0.1 mol
The amount of heat required to melt one mole of iodine is 7.824 Kj /mol
For 0.1 mol;
7.824 Kj /mol × 0.1 mol
0.7824 KJ
C; The attraction between particles causes a gas to condense at low temperatures.
Answer:
1. D
2. B
Explanation:
1. Isotopes vary in neutrons. Due to this variance, the difference in neutrons change the mass of the element.
Note: the amount of protons in an element never changes. The number of protons (the atomic number on the periodic table) identifies the element in question. If you add or subtract protons, you change the element.
2. B-10 and B-11 are two isotopes of the element Boron: One with 10 neutrons, and another with 11 neutrons. Because they contain a variance of neutrons, they do not have the same mass. This cancels choices A and D.
The protons of an element are equal to the atomic number of that element. Borons atomic number is 5 (according to the periodic table), so it contains 5 protons. This cancels choice C as the element with 6 protons is Carbon.
Note: The amount of protons in an atom is balanced out by the same amount of electrons to allow for a neutral charge of the element (i.e., the protons, which contain a positive charge, and electrons, which contain a negative charge, cancel each other out. In the case of Boron: +5 protons - 5 electrons = 0 charge). This is why choice B is correct, as the consideration of an ion is not necessary for this question.
