January 2012 Chemistry Regents #1-10
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Questions | Answer | Link | Explanations |
| 1. What is the number of electrons in a completely filled second shell of an atom? (1) 32 (2) 2 (3) 18 (4) 8 | 4 | link
| 2-8-18-32 the second shell can hold up to 8 electrons |
| 2. What is the number of electrons in an atom that has 3 protons and 4 neutrons? (1) 1 (2) 7 (3) 3 (4) 4 | 3 | link | atoms are neutral, so protons must equal electrons |
| 3. As a result of the gold foil experiment, it was concluded that an atom (1) contains protons, neutrons, and electrons (2) contains a small, dense nucleus(3) has positrons and orbitals (4) is a hard, indivisible sphere | 2 | link
| there are 2 conclusions 1 is open space 2 is a positive DENSE NUCLEUS |
4 Which statement describes the distribution of charge in an atom?(l) A neutral nucleus is surrounded by one or more negatively charged electrons. (2) A neutral nucleus is surrounded by one or more positively charged electrons. (3) A positively charged nucleus is surrounded by one or more negatively charged electrons. (4) A positively charged nucleus is surrounded by one or more positively charged electrons. | 3 | link | the nucleus is positive and the electron cloud in negative |
5 Which atom in the ground state has an outermost electron with the most energy? (1) Cs (3) Li (2) K (4) Na | 1 | link
| Cs has an electron in the 6th energy level |
6 Which particle has the least mass?(1) alpha particle (3) neutron (2) beta partic1e (4) proton | 2 | link | beta particle is a high energy electron |
7 The elements in Group 2 are classified as (1) metals (3) nonmetals(2) metalloids (4) noble gases | 1 | link | Group 2 are the Alkaline Earth Metals |
8 Which best includes elements with the most similar chemical properties?(1) Br, Ca, Hg (3) O, S, Se (2) Cr, Pb, Xe (4) N, O , F | 3 | link | They are in the same group |
9 The notation for the nuclide 13755Cs gives information about(1) mass number, only(2) atomic number. only (3) both mass number and atomic number (4) neither mass number nor atomic number | 3 | link | top # is the mass number and the bottom number is the atomic number |
10 Which pair represents two forms of an element in the same phase at STP but with different structures and different properties? (1) I2(s) and I2(g) (3) H2(g) and Hg (g)(2) O2(g) and O3(g) (4) H2O(s) and H2O(l) | 2 | link | O2 and O3 are allotropes of oxygen they are both gases at STP and have different properties |