General Science class 7 Ch 6

What does give the positive charge to the nucleus of an atom?

Protons gives the positive charge to the nucleus of an atom.

Define a cation and an anion?

If a neutral atom loses one or more electrons, it has a net positive charge and is known as a cation. If an atom gains electrons, it has a net negative charge and is known as an anion.

What is chemical formula?

Describing a molecule in the form of symbols and valences is called the chemical formula.

List the names, charges and locations of three kinds of particles that make up an atom?

Atoms are made of small particles called protons, electrons and neutrons.

Electrons: They have negative charge. They revolve around the nucleus.

Protons: They have positive charge. They lie in the Nucleus.

Neutron: They have no charge. They lie in the Nucleus.

How are the isotopes of an element alike and how are they different?

Similarity: They have same atomic number.

Difference: They have different mass number.

A chlorine atom has 17 protons and 18 neutrons. What is is mass number?

What is its atomic number?

Mass Number = Number of Protons + Number of Neutrons

Mass Number: 17+18 = 35

Atomic Number = Number of Protons

Atomic number = 17

Why the electrical charge on an atom is zero or neutral?

Number of protons iin an atom are equal to number of electrons. That’s why atom is neutral.