June 2017 Chemistry Regents #1-5
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Questions | Answer | Links | Explanations |
1. Which statement describes the structure of an atom? (1) The nucleus contains positively charged electrons. (2) The nucleus contains negatively charged protons. (3) The nucleus has a positive charge and is surrounded by negatively charged electrons. (4) The nucleus has a negative charge and is surrounded by positively charged electrons. | 3 | link | electrons are negative and outside the nucleus protons are positive and are located in the nucleus with the neutral neutrons |
2. Which term is defined as the region in an atom where an electron is most likely to be located? (l) nucleus (2) orbital (3) quanta (4) spectra | 2 | link | electrons are located in orbitals |
3. What is the number of electrons in an atom of scandium? (1) 21 (3) 45 (2) 24 (4) 66 | 1 | link | atoms are neutral so protons equal electrons scandium is element number 21, which is the number of protons |
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4. Which particle has the least mass? (1) a proton (3) a helium atom (2) an electron (4) a hydrogen atom | 2 | link | proton=1 amu helium=4amu electron= 1/1836 amu hydrogen=1amu |
5. Which electron transition in an excited atom results in a release of energy? (1) first shell to the third shell (2) second shell to the fourth shell (3) third shell to the fourth shell (4) fourth shell to the second shell | 4 | link | an electron that falls to a lower energy level releases energy FYI...3 go up... 1 go down |
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