Chemistry Regents June 2025

Which sequence of historic developments led to the modern model of the atom?

• electrons in shells outside a nucleus, hard sphere, mostly empty space

• electrons in shells outside a nucleus, mostly empty space, hard sphere

• hard sphere, electrons in shells outside a nucleus, mostly empty space

• hard sphere, mostly empty space, electrons in shells outside a nucleus

Which statement compares the energy of an electron in the third shell of a rubidium atom to the energy of an electron in a different shell of the same atom?

• An electron in the third shell has less energy than an electron in the second shell.

• An electron in the third shell has less energy than an electron in the first shell.

• An electron in the third shell has more energy than an electron in the first shell.

• An electron in the third shell has more energy than an electron in the fifth shell.

When an electron in an atom returns from a higher energy state to a lower energy state

• the atom becomes a negative ion

• the atom becomes a positive ion

• a specific amount of energy is emitted

• a specific amount of energy is absorbed

Tags

NGSS.HS-PS4-3

The atomic mass of chlorine is the weighted average of the

• radioactive isotopes of chlorine

• naturally occurring isotopes of chlorine

• artificially produced isotopes of chlorine

• radioactive and artificial isotopes of chlorine

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

• atomic mass

• atomic number

• ionization energy

• electronegativity

Which element symbol represents a metalloid?

• Ba

• Cs

• Te

• Xe

Which term identifies a chemical property that can be used to differentiate a sample of sodium from a sample of gold?

• density

• mass

• reactivity

• temperature

Which term identifies the type of matter that is composed of two or more different elements chemically combined in a fixed ratio?

• solution

• compound

• homogeneous mixture

• heterogeneous mixture

Tags

NGSS.HS-PS1-1

The coefficients in a balanced equation represent the

• atomic numbers of each element in the reaction

• mass numbers of the reactants and products

• mass ratio of substances in the reaction

• mole ratio of substances in the reaction

Given the equation representing a reaction: Br + Br → Br₂ Which statement describes what occurs during this reaction?

• Energy is released as bonds are formed.

• Energy is released as bonds are broken.

• Energy is absorbed as bonds are formed.

• Energy is absorbed as bonds are broken.

Tags

NGSS.HS-PS1-4