Chemical Bonding and Reactions
Aligned to HS-PS1 — Next Generation Science Standards.
What this lesson teaches
Atoms bond by sharing or transferring electrons to become stable. In reactions, bonds break and form, rearranging atoms into new substances.
Worked examples
Example 1
Sodium gives an electron to chlorine, forming the ionic compound NaCl (table salt) — a new substance with new properties.
Example 2
In a covalent bond nothing is transferred: two hydrogen atoms share a pair of electrons so both behave as if their shell is full.
Example 3
Compound properties do not average the elements. Sodium explodes in water and chlorine is poisonous; sodium chloride is table salt.
Practice questions
- What is the difference between ionic and covalent bonds?
- In a reaction, what happens to chemical bonds?
- Why do atoms bond at all?
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Enlaces Químicos y Reacciones
Los átomos se enlazan compartiendo o transfiriendo electrones para volverse estables. En las reacciones, los enlaces se rompen y se forman, reorganizando los átomos en nuevas sustancias.
Ejemplo 1: El sodio le cede un electrón al cloro, formando el compuesto iónico NaCl (sal de mesa) — una nueva sustancia con nuevas propiedades.
Ejemplo 2: En un enlace covalente no se transfiere nada: dos átomos de hidrógeno comparten un par de electrones para que los dos se comporten como si su capa estuviera llena.
Ejemplo 3: Las propiedades de un compuesto no promedian las de los elementos. El sodio explota en agua y el cloro es venenoso; el cloruro de sodio es sal de mesa.
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