Chemistry Old Regents January 2018

1 The results of the gold foil experiment led to the conclusion that an atom is

• mostly empty space and has a small, negatively charged nucleus

• mostly empty space and has a small, positively charged nucleus

• a hard sphere and has a large, negatively charged nucleus

• a hard sphere and has a large, positively charged nucleus

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2 Atoms are neutral because the number of

• protons equals the number of neutrons

• protons equals the number of electrons

• neutrons is greater than the number of protons

• neutrons is greater than the number of electrons

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3 In the ground state, valence electrons of a krypton atom are found in

• the first shell

• the outermost shell

• both the nucleus and the first shell

• both the first shell and the outermost shell

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4 According to the wave-mechanical model of the atom, electrons are located in

• orbitals

• circular paths

• a small, dense nucleus

• a hard, indivisible sphere

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5 Which electron configuration represents the electrons in an atom of sodium in the ground state at STP?

• 2-8-1

• 2-8-6

• 2-7-2

• 2-7-7

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NGSS.HS-PS1-1

6 The elements on the Periodic Table of the Elements are arranged in order of increasing

• atomic number

• mass number

• number of neutrons

• number of valence electrons

7 Which element is malleable at STP?

• chlorine

• copper

• helium

• sulfur

8 At 298 K and 1 atm, which noble gas has the lowest density?

• Ne

• Kr

• Xe

• Rn

9 Which two terms represent types of chemical formulas?

• empirical and molecular

• polar and nonpolar

• synthesis and decomposition

• saturated and concentrated

10 Which quantities are conserved in all chemical reactions?

• charge, pressure, and energy

• charge, mass, and energy

• volume, pressure, and energy

• volume, mass, and pressure

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