What is the ratio of hydrogen atoms (H) to oxygen atoms (O) in 2 L of water? Enter the simplest whole number ratio in order of hydrogen to oxygen, respectively. |
2, 1 |
How many atoms of hydrogen (H) are present in 200 molecules of ammonia (NH3)? |
600 H atoms |
A solution of ammonia and water contains 2.50×1025 water molecules and 5.50×1024 ammonia molecules. How many total hydrogen atoms are in this solution? |
6.65 x 10^25 H atoms |
Specify the number of protons, neutrons, and electrons in the neutral atom iron-56. |
26, 30, 26 protons, neutrons, electrons |
The ion S^2− has _____ protons and _____ electrons. |
16, 18 |
What isotope has 13 protons and 14 neutrons? |
Aluminum-27 |
Which element does X represent in the following expression: 41 (superscript) 20 (subscript)X? |
Ca |
What is the atomic mass of a hypothetical element that consists of the following isotopes in the indicated natural abundances? Express your answer to three significant figures and include the appropriate units. |
90.7 amu |
What is the atomic mass of the element that consists of the following isotopes in the indicated natural abundances? Express your answer to three significant figures and include the appropriate units. |
58.7 amu |
Classify the following elements as main group elements, transition metals, or inner transition metals. |
Main group elements: -Mg -Bi -S Transition Metals: -Pd -Fe Inner transition metals: -Fm |
Classify the following elements as halogens, alkali metals, alkaline earth metals, or noble gases. |
Halogens: -Br -F Alkali metals: -Fr -Li Alkaline earth metals: -Ca Noble gases: -Kr |
Match each element to its period. |
Period 1: H Period 2: Be Period 3: Al Period 4: Ni Period 5: In Period 6: W Period 7: Rf |
Classify the following elements as metal, nonmetal, or metalloid (semimetal). |
Metal: -K -Mn Nonmetal: -P -Ne Metalloid -Ge -As |
Which of the following could be the structure of C3H6O3? |
B |
Tyrosine contains 11 hydrogen atoms, 9 carbon atoms, 3 oxygen atoms, and 1 nitrogen atom. What is the chemical formula for tyrosine? |
C9H11NO3 |
A certain compound is made up of two bromine atoms, one nitrogen atom, and one chlorine atom. What is the chemical formula of this compound? |
NBr2Cl |
Strontium bromide contains only strontium and bromine. What is the formula for this compound? |
SrBr2 |
Which of the following would you expect to be a molecule and which would you expect to be part of an ionic solid? |
Molecular: -HCl -SO -CO Ionic: -NaI -KCl -MgO -CaS -KF |
Classify the following compounds as having covalent or ionic bonds. |
Covalent Bond: -dinitrogen trioxide -carbon dioxide Ionic Bond: -sodium bromide -magnesium nitride -aluminum oxide -calcium chloride |
Match each diagram to the atom or ion it represents. |
P: 15+ 15- P^3+: 15+ 12- P^3-: 15+ 18- Mg: 12+ 12- Mg^2+: 12+ 10- Mg^2-: 12+ 14- |
What is the charge on the most stable ion of each of the following elements? |
1+: K 2+: Ba, Mg 3+: Al 3-: N 2-: O, S 1-: I |
Give the systematic name for the compound Mg(NO3)2. |
magnesium nitrate |
Give the systematic name for the compound Mn2(SO4)3. |
manganese(III) sulfate |
Enter the formula for the compound beryllium oxide. |
BeO |
Enter the formula for the compound lead(II) phosphate. |
Pb3(PO4)2 |
What is the name for the compound NO2? |
nitrogen dioxide |
What is the name for the compound N2H4? |
dinitrogen tetrahydride |
Based on the data Thomson collected in his experiments using cathode rays, the concept of atomic structure was modified. Which of the following statements about the atomic structure were validated by his cathode ray experiments? |
-Matter contains negative charge and by inference positive charge. -Cathode rays have mass. -There are subatomic size particles in an atom. -Particles of the cathode rays are fundamental to all matter. |
Based on the data gathered in Millikan's oil-drop experiments, the concept of atomic structure was modified. Which of the following aspects of the structure of the atom was validated by these experiments? |
-charge on an electron -mass of an electron |
Based on the data gathered in the Rutherford's scattering experiments, the concept of atomic structure was modified. Which of the following aspects of the structure of the atom were validated by these experiments? |
-the nuclear density being large -the charge on the nucleus being positive -the existence of the atomic nucleus -most of the atomic volume being empty space |