Answer:
B. +3 and +6
Explanation:
The values of the Z
is estimated by subtracting the core electrons from the atomic number of the element.
Oxygen has an atomic number of 8, 6 valence electrons, and 2 core electrons. Therefore the value of Z = 8-2 = +6
Boron has an atomic number of 5, 3 valence electrons and 2 core electrons. Therefore, the value of Z = 5-2 = +3
Answer:
The largest anthropogenic source of CO in the United States is vehicle emissions.
Explanation:
Answer:
i can help you but it only depends on what your working on ?
Explanation . Claim: How solar cells different from silicon. evidence-The most promising group of these new materials are called hybrid lead halide perovskites, which appear to promise a revolution in the field of solar energy.Pure crystalline silicon is a poor conductor of electricity as it is a semiconductor material at its core.In a solar cell, the layers are positioned next to each other and that way an electric field is created.Crystalline silicon cells are made of silicon atoms connected to one another to form a crystal lattice. This lattice provides an organized structure that makes conversion of light into electricity more efficient.Solar cells are made from silicon boules. These are polycrystalline structures that have the atomic structure of a single crystal. The most commonly used method for the creation of the boule is known as the Czochralski method.
Reasoning: Traditional crystalline solar cells are typically made of silicon. An organic solar cell uses carbon-based materials and organic electronics instead of silicon as a semiconductor to produce electricity from the sun. Organic cells are also sometimes referred to as “plastic solar cells” or “polymer solar cells” hybrid perovskites Libai Huang, assistant professor of chemistry at Purdue, says the new material, called a hybrid perovskites, would create solar cells thinner than conventional silicon solar cells, and is also flexible, cheap and easy to make.
Answer:
Mass = 713.4 ×10⁻⁴ g
Explanation:
Given data:
Number of moles of calcium phosphate = 2.3×10⁻⁴ mol
Mass of calcium phosphate = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of calcium phosphate is 310.18 g/mol
by putting values,
2.3×10⁻⁴ mol = mass / 310.18 g/mol
Mass = 2.3×10⁻⁴ mol × 310.18 g/mol
Mass = 713.4 ×10⁻⁴ g
At the center of every atom lies a small, dense "nucleus" that is positively charged.
Atom is the smallest unit of matter. It is made up of electrons, protons and neutrons. Electrons are negatively charged particles that are found scattered in different energy levels outside the nucleus. Protons are positively charged particles present inside the nucleus. Neutrons do not carry charge and found inside the nucleus. Thus, protons and neutrons make up the nucleus of an atom. Since, protons are positively charged and neutrons are uncharged particles, the charge of nucleus becomes positive.
