mass number

简明释义

质量数

英英释义

例句

1.Isotopes of an element differ in their mass number 质量数 due to varying numbers of neutrons.

元素的同位素因中子数量的不同而在其质量数 质量数上有所差异。

2.The mass number 质量数 of an atom is the total number of protons and neutrons in its nucleus.

一个原子的质量数 质量数是其核心中质子和中子的总数。

3.In a periodic table, you can often find the mass number 质量数 listed next to the element symbol.

在周期表中，你通常可以在元素符号旁边找到质量数 质量数。

4.The mass number 质量数 helps determine the stability of an isotope.

在确定同位素的稳定性时，质量数 质量数是一个重要因素。

5.When calculating the mass number 质量数, remember to add the number of protons and neutrons together.

在计算质量数 质量数时，请记得将质子和中子的数量相加。

作文

Understanding the concept of mass number is fundamental to grasping the basics of atomic structure in chemistry. The mass number, defined as the total number of protons and neutrons in an atomic nucleus, plays a crucial role in determining the identity and stability of an element. Each element on the periodic table is represented by its atomic symbol, which includes the mass number as part of its notation. For example, carbon is often represented as 12C, where 12 indicates the mass number of the most common isotope of carbon, which contains six protons and six neutrons.The significance of the mass number extends beyond mere identification of elements; it also influences the properties of isotopes. Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons, resulting in different mass numbers. For instance, while carbon-12 has a mass number of 12, carbon-14 has a mass number of 14 due to the presence of two additional neutrons. This difference in mass number leads to varying stability and radioactive properties among isotopes, which can be harnessed in fields such as medicine and archaeology.In practical applications, the mass number is essential for calculations involving atomic mass and molecular weight. Chemists often use the mass number to determine the average atomic mass of elements based on their isotopic distribution. This average is crucial for stoichiometric calculations in chemical reactions, where precise measurements of reactants and products are required. By understanding the mass number, scientists can predict how different elements will interact and the quantities involved in chemical reactions.Moreover, the mass number is a key factor in nuclear chemistry and physics. In nuclear reactions, the conservation of mass number is a fundamental principle. During processes such as fission or fusion, the total mass number before and after the reaction must remain constant, allowing scientists to balance nuclear equations accurately. This principle is vital for understanding energy production in stars, including our sun, where hydrogen nuclei fuse to form helium, releasing immense amounts of energy in the process.In conclusion, the mass number is not just a numerical value; it is a gateway to understanding the intricate world of atoms and their interactions. From identifying elements and their isotopes to calculating molecular weights and balancing nuclear reactions, the mass number serves as a cornerstone in the study of chemistry and physics. By mastering this concept, students and professionals alike can deepen their comprehension of the natural world and its underlying principles.

理解质量数的概念对于掌握化学中原子结构的基础知识至关重要。质量数被定义为原子核中质子和中子的总数，它在决定元素的身份和稳定性方面发挥着关键作用。周期表上的每个元素都由其原子符号表示，其中包括质量数作为其标记的一部分。例如，碳通常表示为12C，其中12表示最常见的碳同位素的质量数，它包含六个质子和六个中子。质量数的重要性超越了元素的简单识别；它还影响同位素的性质。同位素是某一特定化学元素的变体，具有相同数量的质子但不同数量的中子，从而导致不同的质量数。例如，虽然碳-12的质量数为12，但碳-14的质量数为14，因为它多了两个中子。这种质量数的差异导致同位素之间稳定性和放射性特性的不同，可以在医学和考古等领域得到应用。在实际应用中，质量数对于涉及原子质量和分子量的计算至关重要。化学家经常使用质量数根据同位素分布来确定元素的平均原子质量。这个平均值对于化学反应中的计量计算至关重要，在这些反应中，需要精确测量反应物和产物。通过理解质量数，科学家可以预测不同元素之间的相互作用以及化学反应中涉及的数量。此外，质量数是核化学和物理学中的一个关键因素。在核反应中，质量数的守恒是一个基本原则。在裂变或聚变等过程中，反应前后的总质量数必须保持不变，这使得科学家能够准确地平衡核方程式。这个原则对于理解恒星中的能量产生至关重要，包括我们的太阳，在那里，氢核融合形成氦，同时释放出巨大的能量。总之，质量数不仅仅是一个数字；它是理解原子及其相互作用复杂世界的入口。从识别元素及其同位素到计算分子量和平衡核反应，质量数作为化学和物理学研究的基石。通过掌握这一概念，学生和专业人士可以加深对自然世界及其基本原理的理解。