Chemistry Guided Notes Atoms • An atom is the smallest unit of matter that retains the properties of an element. 原子是保持元素特性的最小物质单位 • • Protons: Positive charge | 质子：正电荷 • Neutrons: No charge | 中子：无电荷 • Electrons: Negative charge | 电子：负电荷 Protons, neutrons, and electrons are called subatomic particles 质子、中 子和电子称为亚原子粒子 Using the Periodic Table to Determine Protons, Neutrons, and Electrons • 使用周期表确定质子、中子和电子的数量 • The atomic number (found in the top left corner) represents the number of protons in an atom 原子序数（位于左上角）表示原子中的质子数 • Calculating Electrons • In a neutral atom, the number of electrons equals the number of protons 在一个中性原子中，电子数等于质子数 • Finding Neutrons • Neutrons can be calculated by subtracting the atomic number from the atomic mass (rounded to the nearest whole number) 中子数可 以通过从原子质量（四舍五入到最近的整数）中减去原子序数来计算 • Neutrons = Atomic Mass - Atomic Number • 公式：中子 = 原子质量 - 原子序数 Atoms • Atoms are on the periodic table. 原子在元素周期表上 Chemistry Guided Notes • Atoms are NEUTRAL meaning they have equals numbers of protons and electrons. 原子是中性的，这意味着它们的质子和电子数量相等。 • In the nucleus are protons and neutrons, electrons are orbiting around the nucleus. 原子核中有质子和中子，电子围绕原子核运行 Ions • An ion is an atom or molecule that has a net electrical charge 离子是具有 净电荷的原子或分子 • Types of Ions: • Cation: Positively charged ions formed by losing electrons 通过失 去电子形成的带正电离子 • Anion: Negatively charged ions formed by gaining electrons. 通过 获得电子形成的带负电离子 Metals and Electrons • Metals: Tend to lose electrons to achieve a stable electron configuration 金属：倾向于失去电子以达到稳定的电子配置 • Example: Sodium (Na) loses one electron to become Na⁺ • 例子：钠（Na）失去一个电子变成 Na⁺ Nonmetals and Electrons • Nonmetals: Tend to gain electrons to fill their outer shell and achieve stability. 非金属：倾向于获得电子以填满外层并达到稳定性 • Example: Chlorine (Cl) gains one electron to become Cl⁻ • 例子：氯（Cl）获得一个电子变成 Cl⁻ Ions 1. What is the charge of a cation? | 阳离子的电荷是什么？ Chemistry Guided Notes 2. How do ions form? | 离子是如何形成的？ 3. Identify if the following are ions or atoms: Na-, Cl, O-2. | 确定以下是离子还 是原子：Na-，Cl，O-2。 Isotopes 同位素 • Definition: Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. 同位 素是特定化学元素的变体，它们具有相同的质子数但中子数不同 • Carbon-12 (¹²C): 6 protons, 6 neutrons 碳-12 (¹²C): 6 个质子，6 个中子 • Carbon-14 (¹⁴C): 6 protons, 8 neutrons 碳-14 (¹⁴C): 6 个质子，8 个中子 Properties • Isotopes of an element have similar chemical properties 元素的同位素具有 相似的化学性质 • Some isotopes are stable, while others are radioactive 一些同位素是稳定 的，而另一些是放射性的 Uses of Isotopes Applications: • Carbon dating (¹⁴C) for determining the age of fossils. 碳定年 （¹⁴C）用于确定化石的年龄 • Medical imaging using radioactive isotopes like Technetium-99m. 使 用放射性同位素如锝-99m 进行医学成像 Key Points Chemistry Guided Notes • Atoms are the building blocks of matter. | 原子是物质的基本单位 • Ions are formed when atoms gain or lose electrons. | 当原子获得或失去电 子时，会形成离子 • Isotopes: Atoms of the same element with different numbers of neutrons 具有不同中子数的同一元素的原子