Holt Chemistry Questions
Calculate the numbers of protons, electrons, and neutrons for each of the following isotopes of 42/20 Ca and 44/20 Ca.
Both have 20 protons and 20 electrons. Calcium-42 has 22 neutrons. Calcium-44 has 24 neutrons.
Chlorine has two stable isotopes, chlorine-35 and chlorine-37. The atomic number of chlorine is 17. Calculate the numbers of Protons, electrons, and neutrons each isotope has.
Both isotopes have 17 protons and 17 electrons. Chlorine-35 has 18 neutron and chlorine-37 has 20 neutrons.
What are two differences between compounds and mixtures?
Compounds have properties that differ from the properties of their components, but mixtures have properties that often reflect the properties of the components that make up the mixture. A compound has a definite composition, so the components must be present in exact ratios. Mixtures can be varying compositions, so the proportions of the components can vary.
Identify either of the following as an element, a compound, a homogenous mixture or a heterogenous mixture.
1. CH4-compound 2. S8-element 3. distilled water-compound 4. salt water-homogenous mixture 5. CH2O-compound 6. concrete-heterogenous mixture
Write the symbol for element x, which 22 electrons and 22 neutrons.
44/22 X
How is a homogenous mixture different from a heterogenous mixture?
In a homogenous mixture, the components are distributed evenly throughout, so the properties are same throughout. In a heterogenous mixture, the components are not evenly distributed, so there are regions of the mixture with different properties.
How are atoms and molecules related?
A molecule consists of one or more atoms.
Define the term compound.
A substance made up of atoms of two or more different elements joined by chemical bonds.
How are isotopes of the same element alike?
All isotopes of an element have the same number of Protons and electrons.
How does an element differ from a compound?
An element is made up of one type of atom, but a compound must be made up of atoms of two or more different elements.
Are Hydrogen-3 and Helium-3 isotopes of the same element? Explain your answer.
No, they are isotopes of different elements, because they have different atomic numbers. All isotopes of an element have the same atomic number, not the same mass number.
Calculate the atomic number and mass number of an isotope that has 56 electrons and 82 neutrons?
The atomic number of this element is 56, and the mass number is 138.
Describe the differences between electrons, protons and neutrons.
The mass of an electron is much smaller than the mass of a proton or the mass of a neutron. Protons have a +1 charge, electrons have a -1 charge and neutrons have no charge. Protons and Neutrons make up the atomic nucleus, while electrons surround the nucleus.
What is the smallest number of elements needed to make a compound?
Two
Determine of electrons, protons and neutrons for each of the following: a. 80/35 Br b. 106/46 Pd c. 133/55 Cs
a.35 electrons, 35 protons, 45 neutrons. b.46 electrons, 46 protons, 60 neutrons. c. 55 electrons, 55 protons, 78 neutrons.
What are two types if pure substances?
elements and compounds.
