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Structure of Atoms
In your element
Chemical Formulas
Chemical Properties
Chemical Reactions
100
An atom consists mostly of empty space with: A.) protons orbiting a dense nucleus made of electrons and neutrons B.) electrons orbiting a dense nucleus made of protons and neutrons C.) neutrons and protons orbiting a cloud of electrons D.) electrons and protons orbiting a cloud of neutrons
What is B. electrons orbiting a dense nucleus made of protons and neutrons?
100
An example of an element: 1.) H2O 2.) CO2 3.) He 4.) NaCl
What is He?
100
The atoms of a certain element each contain 11 protons and 1 valence electron. The statement that correctly identifies this element and describes its chemical reactivity: A. The element is sodium, and it is highly reactive. B. The element is fluorine and it is not very reactive . C. The element is sodium, and it is not very reactive. D. The element is fluorine, and it is highly reactive.
What is A. The element is sodium, and it is highly reactive?
100
heat CaCO3 -----> CaO + CO2 In the chemical reaction shown above the products are best classified as: A. two elements B. one element and one compound C. two compounds D. two compounds and one element
What is C. two compounds?
200
The statement that best describes an electron: A.) It has no charge and about the same mass as a proton. B.) It has a negative charge and much less mass than a proton. C.) It has a positive charge and much more mass than a neutron. D.) It has a negative charge and about the same mass as a neutron.
What is B. It has a negative charge and much less mass than a proton?
200
The number of elements in the below reaction: C3H8 + 5O2 --->3CO2 + 4H2O
What is 3?
200
Number at lower right of element's symbol in a formula; shows number of atoms for each element:
What is a subscript?
200
A Chemist is identifying the elements present in a sample of seawater. The characteristic of an element's atoms that always determines the element's identity is: A. The number of protons B. The number of neutrons C. The location of valence electrons D. The number of valence electrons
What is A. The number of protons?
200
color change, temperature change, gas formation, or precipitate (solid) formation is often observed when a new substance(s) is formed during a chemical reaction
What is evidence of a chemical reaction
300
An atom has 25 protons, 30 neutrons, and 25 electrons. The charge of the atom's nucleus is: A.) +25 B.) +30 C.) -25 D.) -30
What is A. +25?
300
Name the compound: A.) Aluminum B.) Copper C.) Iron D.) Steel
What is D. Steel?
300
In this compound are there twice as many oxygen atoms as hydrogen: A. H3PO4 B. H2SO4 C. HClO3 D. H2O
What is B. H2SO4?
300
Aluminum, Sulfur, and Chlorine are elements found on the periodic table. Tests involving these three elements would show that at normal room temperature: A. Sulfur is malleable and aluminum conducts electricity B. Chlorine is malleable and conducts electricity C. Aluminum is malleable and conducts electricity D. All three elements are malleable and conduct electricity
What is C. Aluminum is malleable and conducts electricity?
300
Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. The best evidence that a chemical reaction occurs when coal burns is: A. The shape of the coal changes. B. Oxygen is present. C. A new substance is produced. D. Coal is made up of more than one element.
What is C. a new substance is produced?
400
The mass number of a potassium (K) atom that has 20 neutrons: A.) 18 B.) 19 C.) 20 D.) 39
What is D. 39?
400
The elements found in NH3: A.) Nitrogen and Helium B.) Nitrogen and Hydrogen C.) Nickel and Hydrogen D.) Nickel and Helium
What is B. Nitrogen and Hydrogen?
400
The chemical formula for sodium sulfate is Na2SO4. The number of sulfur atoms are in the formula for sodium sulfate: A. 1 B. 2 C. 6 D. 7
What is A. 1?
400
A student is studying calcium, a highly reactive element that humans need for strong bones. The characteristic of calcium is mostly closely related to its chemical reactivity: A. The 20 protons in each atom of calcium B. The density of calcium C. The atomic mass of calcium, which is 40.078 amu D. The 2 valence electrons in each atom of calcium
What is D. The 2 valence electrons in each atom of calcium?
500
An atom of a certain element has 36 protons, 36 electrons, and a mass number of 84. At room temperature this element is a very stable gas. The number of neutrons in this atom:
What is 48?
500
Acetaminophen (C8H9NO2) is an organic compound. Name the element in the compound that is required for it to be classified as organic: A.) Carbon B.) Hydrogen C.) Oxygen D.) Chlorine
What is A. Carbon?
500
Compound that includes carbon along with the element(s) hydrogen, oxygen, nitrogen, phosphorus, and/or sulfur:
What is an organic compound?
500
A researcher wants to experiment with an element that reacts like phosphorus (P) but has a greater atomic mass. The element the researcher should select for the experiment is: A. Nitrogen (N) B. Sulfur (S) C. Arsenic (As) D. Silicon (Si)
What is C. Arsenic (As)?