Question

Use the portion of the periodic table shown below to answer the questions.

Answer 1

Part 1: Potassium, and Rubidium.
Part 2: Calcium has 20 protons and 20 electrons because the atomic number for calcium is 20 and that determines how many protons there are and in an atom, the number of protons is the same number of electrons. Calcium has about 20 neutrons. I got the number of Neutrons by subtracting the mass number(40.078) and the atomic number(20), I got 20.078. Round to the nearest whole number because you cannot have half or partial neutron. So, Calcium has 20 protons, 20 electrons, and 20 neutrons,

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Answer 2

Answer:

For 1: The two elements having same properties as sodium are potassium and rubidium.

For 2: Calcium has 20 protons, 20 electrons and 20 neutrons.

Explanation:

• For 1:

The elements which belong to the same group, tend to have same properties. Group represents the vertical row in the periodic table. Hence, the elements which have same properties as sodium are potassium and rubidium.

• For 2:

Atomic number is defined as the number of protons or electrons in an element.

Atomic number = Number of electrons = Number of protons

Atomic mass is defined as the sum of number of protons and neutrons in an element.

Atomic mass = Number of protons + Number of neutrons

Atomic number of calcium is 20. So, number of protons and electrons will be 20.

Atomic mass of calcium is 40.

40 = Number of neutrons + 20

Number of neutrons = 20

Hence, calcium has 20 protons, 20 electrons and 20 neutrons.