Answer:
i. Matter consists of tiny particles called atoms
ii. Atoms are indestructible. In chemical reactions, the atoms rearrange but they do not themselves break apart.
iii. In any sample of a pure element, all the atoms are identical in mass and other properties.
iv. The atoms of different elements differ in mass and other properties.
v. When atoms of different elements combine to form a given compound, the constituent atoms in the compound are always present in the same fixed numerical ratio.
Learning objective 1.2 – explain how the concept of atoms developed.
82. What are isotopes?
Answer: Isotopes are atoms of an element with the same number of protons but different numbers of neutrons.
Learning objective 1.3 – describe the structure of the atom.
83. Common table salt, sodium chloride, contains 2.87 g of sodium for every 4.43 g of chloride. If a sample of sodium chloride contains 7.12 g of chloride, what mass of sodium does it contain?
Answer: 4.62 g
Learning objective 1.2 – explain how the concept of atoms developed.
84. Magnesium chloride, contains 6.08 g of magnesium for every 17.73 g of chloride. If a sample of magnesium chloride contains 3.47 g of magnesium, what mass of chloride does it contain?
Answer: 10.13 g
Learning objective 1.2 – explain how the concept of atoms developed.
85. Lithium fluoride, contains 4.75 g of fluoride for every 1.74 g of lithium. If a sample of lithium fluoride contains 0.77 g of lithium, what mass of fluoride does it contain?
Answer: 2.11 g
Learning objective 1.2 – explain how the concept of atoms developed.
86. What is the name given to chemical reactions that involve the transfer of one or more electrons between chemical species?
Answer: Redox reactions.
Learning objective 1.5 – detail the role of electrons in atoms.
87. What does the acronym IUPAC stand for?
Answer: International Union for Pure and Applied Chemistry.
Learning objective 1.4 - explain the basis of the periodic table of the elements.
88. The atomic mass unit is defined as 1/12 of what element?
Answer: 12C
Learning objective 1.3 – describe the structure of the atom.
89. What is the mass of an electron?
Answer: 9.109 x 10-31 kg
Learning objective 1.3 – describe the structure of the atom.
90. What are the two commonly known spin states of an electron?
Answer: Spin up and spin down.
Learning objective 1.5 – detail the role of electrons in atoms.
91. What metalloids are commonly used in silicon chips and transistors?
Answer: Silicon and Germanium.
Learning objective 1.4 - explain the basis of the periodic table of the elements.
92. What is the minimum number of atoms in a molecule?
Answer: Two.
Learning objective 1.1 – define atoms, molecules, ions, elements and compounds.
93. In chemistry, the term compound refers to what?
Answer: Compounds are substances containing two or more elements in a definite and unchanging proportion.
Learning objective 1.1 – define atoms, molecules, ions, elements and compounds.
94. Which French chemist proposed the law of conservation of mass?
Answer: Antoine Lavoisier.
Learning objective 1.1 – define atoms, molecules, ions, elements and compounds.
95. Briefly describe the basis of ordering elements in Mendeleev’s original periodic table.
Answer: Mendeleev ordered the elements by increasing atomic mass.
Learning objective 1.4 - explain the basis of the periodic table of the elements.
96. Briefly describe the basis of ordering elements in the modern periodic table.
Answer: Elements are ordered by increasing atomic number.
Learning objective 1.4 - explain the basis of the periodic table of the elements.
97. Briefly describe Rutherford's model of the atom.
Answer: Every atom has a tiny positively charged central core, a nucleus, and this constitutes most of the mass of an atom. Negatively charged electrons surround the nucleus, occupying a large volume.