Struktur Atom (2) | Cara Paling Mudah Menentukan Jumlah Proton, Neutron, dan Elektron

Summary

In this educational video, the presenter explains how to interpret atomic symbols, including how to determine atomic number, mass number, and the quantities of protons, neutrons, and electrons. Using examples like sodium (Na) and calcium (Ca), the video illustrates the relationships between atomic properties. It also covers ions, explaining how their charge affects electron count, with positive ions losing electrons and negative ions gaining them. The tutorial concludes with a review of key concepts to reinforce understanding of atomic structure and ions in chemistry.

Takeaways

• 😀 Atomic symbols represent elements, where the upper number is the mass number (A) and the lower number is the atomic number (Z).
• 😀 The number of protons is equal to the atomic number (Z), and this also represents the number of electrons in a neutral atom.
• 😀 Neutrons can be determined by subtracting the atomic number (Z) from the mass number (A): Neutrons = A - Z.
• 😀 In the example of Sodium (Na), the mass number is 23, atomic number is 11, so the number of protons is 11, neutrons is 12, and electrons is 11.
• 😀 In the example of Calcium (Ca), the mass number is 40, atomic number is 20, so the number of protons is 20, neutrons is 20, and electrons is 20.
• 😀 An ion is an atom that carries a charge, either positive or negative.
• 😀 For positively charged ions (cations), the number of electrons is less than protons, calculated by subtracting the ion's charge from the number of protons.
• 😀 For example, a Sodium ion (Na+) with a +1 charge has 10 electrons (11 protons - 1).
• 😀 For negatively charged ions (anions), the number of electrons is greater than protons, calculated by adding the ion's negative charge to the number of protons.
• 😀 For example, an Oxygen ion (O2-) with a -2 charge has 10 electrons (8 protons + 2).
• 😀 The key takeaway: positive ions lose electrons, while negative ions gain electrons.

Q & A

What is the symbol used to represent the mass number of an atom?

The mass number of an atom is represented by the letter 'A'. It is placed above the atomic symbol.

What does the atomic number (Z) represent in an atomic symbol?

The atomic number (Z) represents the number of protons in an atom and is placed below the atomic symbol.

How can you determine the number of protons in an atom?

The number of protons in an atom is equal to the atomic number (Z).

How do you calculate the number of neutrons in an atom?

The number of neutrons is calculated by subtracting the atomic number (Z) from the mass number (A): Neutrons = A - Z.

What is the relationship between protons and electrons in a neutral atom?

In a neutral atom, the number of protons is equal to the number of electrons.

How do you determine the number of electrons in an atom if it is an ion?

To find the number of electrons in an ion, subtract the ion's charge from the number of protons. For a positive charge, electrons are less than protons, and for a negative charge, electrons exceed protons.

What happens to the number of electrons in a positively charged ion?

In a positively charged ion, the number of electrons decreases because the atom loses one or more electrons.

What happens to the number of electrons in a negatively charged ion?

In a negatively charged ion, the number of electrons increases because the atom gains one or more electrons.

Given the atomic symbol of sodium (Na) with a mass number of 23 and atomic number 11, how many protons, neutrons, and electrons are there in a neutral sodium atom?

In a neutral sodium atom, there are 11 protons, 12 neutrons (23 - 11), and 11 electrons.

For a calcium ion (Ca2+), with a mass number of 40 and atomic number 20, how many electrons does it have?

For the Ca2+ ion, the number of electrons is 18, because it has lost two electrons from the neutral calcium atom (20 protons - 2 charge).