Question

Summary and Conceptual Questions Draw a picture showing the approximate positions of all protons, electrons, and neutrons in an atom of helium-4. Make certain that your diagram indicates both the number and position of each type of particle.

Short answer

Helium-4 has 2 protons and 2 neutrons in the nucleus, and 2 electrons in the electron cloud.

Step-by-step solution

Understand Helium-4 Composition

Helium-4 is an isotope of helium. It consists of two protons, two neutrons, and two electrons. The number 4 represents the atomic mass unit, which is the sum of protons and neutrons. The atomic number of helium is 2, indicating the number of protons, which is equal to the number of electrons in a neutral atom.

Draw the Nucleus

Draw a circle in the center of your diagram to represent the nucleus. Inside the nucleus, you need to place both protons and neutrons. Position two protons (usually represented as small circles labeled 'p') and two neutrons (represented as small circles labeled 'n') inside this central circle.

Place the Electrons

Outside the nucleus, draw a large circle to represent the electron cloud or orbit. This circle should surround the nucleus. Place two electrons (usually represented as small 'e') within this shell. In a helium atom, the electrons are found in the first energy level, which is often depicted as the space surrounding the nucleus.

Label the Diagram

Clearly label each particle type in your drawing to ensure clarity. Mark the protons with a 'p', neutrons with an 'n', and electrons with an 'e'. This will help differentiate each component of the helium atom in your diagram.

Check for Completeness

Review your diagram to ensure that it includes two protons and two neutrons within the nucleus, and two electrons in the surrounding orbital. Each type of particle should be clearly labeled and positioned according to the atomic structure of helium-4.

Key concepts

protons and neutrons

Helium-4, an isotope of the element helium, is composed of protons and neutrons housed within its nucleus. These particles are called nucleons. The count of these particles determines the atomic mass of an isotope. Helium-4, specifically, contains:

- **Two protons:** These are positively charged particles, which play a crucial role in defining the element's identity. The number of protons, known as the atomic number, is what makes helium distinct from other elements. Because helium's atomic number is 2, it always has two protons.

- **Two neutrons:** Unlike protons, neutrons carry no charge. They add mass to the atom and stabilize the nucleus by offsetting the repulsive forces between the positively charged protons. Without neutrons, the nucleus could not stay together.

The nucleus of helium-4 therefore has these nucleons compactly packed together. This arrangement contributes to the stability of helium-4, making it the most stable and common form of helium found naturally.

electron cloud

Surrounding the dense nucleus of helium-4 is an area known as the electron cloud. This is where the atom's electrons reside, creating what we often refer to as an electron shell or energy level. In the case of helium-4, this "cloud" includes:

- **Two electrons:** Electrons are negatively charged particles. In a neutral helium-4 atom, the number of electrons equals the number of protons. This means helium-4 has two electrons, balancing the two positive charges of the protons to maintain electrical neutrality.

The electron cloud isn't a fixed space but rather a probability region where electrons are likely to be found. Unlike the nucleus, which has a compact and exact structure, the electron cloud is more like a fuzzy, roundish shell. Electrons inhabit different energy levels, starting close to the nucleus and extending outward. For helium, both electrons occupy the first energy level, making it a very stable configuration. This simplicity and symmetry of the electron cloud are key to helium's chemical nature as a noble gas, which is generally non-reactive.

atomic nucleus diagram

Drawing an atomic nucleus diagram for helium-4 provides a visual representation of its basic structure. In this depiction:

- **Nucleus placement:** Start by sketching a small, central circle to represent the nucleus. Inside this nucleus, you'll indicate the presence of the four nucleons - the two protons and two neutions. Label these particles clearly with 'p' for protons and 'n' for neutrons. Typically, arranging them in two pairs works well for a simple and easy-to-understand layout.

- **Electron cloud depiction:** Around the nucleus, draw a larger encompassing circle to show the electron cloud or shell. This larger circle should encompass the nucleus entirely. Place two smaller markings within this shell, which symbolize the electrons ('e'). This encircling zone illustrates the region where the two electrons "float" around the nucleus, even though they cannot be located at precise points within this werea.

The resulting diagram provides a basic schematic that emphasizes the separate roles of the nucleus and surrounding electron cloud. It's an essential tool for understanding how these components create a balanced and stable atomic structure in helium-4.