Question

1. what is the number of protons called?
2. what is a family of elements?
3. where did the noble gases get their name?

chlorine - cl

1. chlorine wants to ( take / give away ) one electron, becoming an ( ion / isotope ).
2. what do sodium and chlorine make when combined?
3. compare the properties of each of the following:

	sodium (na)	chlorine (cl)	sodium chloride (nacl)
reactive or stable			stable

Explanation:

1. The number of protons in an atom is called the atomic number. It defines the element's identity.
2. A family of elements, also known as a group, is a vertical column in the periodic table. Elements in the same family have similar chemical properties due to having the same number of valence electrons.
3. Noble gases got their name because they are chemically inert or unreactive under normal conditions. They have a full outer - electron shell, making them very stable.
4. Chlorine has 7 valence electrons and wants to take one electron to achieve a stable octet, becoming an ion (specifically a negatively - charged anion).
5. Sodium and chlorine combine to form sodium chloride (table salt).
6. Sodium chloride is a solid at room temperature. Sodium is highly reactive as it has one valence electron and readily donates it. Chlorine is also reactive as it wants to gain one electron to complete its octet.

Answer:

1. Atomic number
2. A vertical column in the periodic table with elements having similar chemical properties
3. Because they are chemically inert under normal conditions
4. take; ion
5. Sodium chloride
6. State of Matter: Solid; Reactive or Stable: Sodium is reactive, Chlorine is reactive