Fundamental of Chemistry (SPM)

In an atom, the number of electrons is equal to the number of ______.

Metals exist as solid at room temperature. The atoms

• has high kinetic energy

• are arrange closely and orderly

• attraction force are weak

• are arrange close but not in orderly

Melting point is a _____ _______ at which a solid change to liquid at specific pressure.

When a gas change into solid, heat is

• released by the particles

• absorbed by the particles

Fluorine and chlorine are elements in Group 17. Which element is more reactive? Which of the following explains the reason?

• Fluorine is more reactive. Fluorine atom is smaller, nuclear attraction force is stronger to attract electron

• Fluorine is more reactive. Fluorine atom is bigger, nuclear attraction force is weaker to attract electron

• Chlorine is more reactive. Chlorine atom is bigger, nuclear attraction force is weaker to attract electron

• Chlorine is more reactive. Chlorine atom is bigger, nuclear attraction force is stronger to attract electron

Isotopes are atoms of the same element with _____________________________

• same number of protons and same number of neutrons

• same proton number and same nucleon number

• same number of protons but different number of neutrons

• same proton number but different neutron number

Group 18 elements are known as __________

Neon exist as monoatomic gas and inert chemically because

• the atom has achieve a stable nucleon number

• the atom has achieve a stable electron arrangement

• all shells is fully filled with electrons

Lithium and sodium are located in Group 1 in the Periodic Table of Elements and have same chemical properties. Why?

• The atoms have achieve a stable electron arrangement

• The atoms have same number of valence electron which is 1

• The atoms have same number of shells filled with electrons

• The atoms have different size

The reactivity of Group 17 elements __________ when going down the group.