k shell can accommodate 2 electrons.

 k is the first shell in an atom, followed by the l shell, m shell and n shell. The l shell contains 8 electrons, the m shell contains 18 electrons, and the n shell contains 32 electrons.

As we move down the group, the number of shells increases, and thus losing electrons becomes easy for an atom. Thus, the metallic character increases down the group.

Calcium is an alkaline earth metal, belonging to Group 2 of the periodic table. It has two valence electrons, which it readily loses to form a +2 charge, making it highly reactive, though less so than alkali metals. Alkaline earth metals like calcium play vital roles in biological and geological processes. For instance, calcium is essential in bone formation, muscle function, and cell signaling. Its reactivity, particularly its tendency to form calcium oxide and calcium carbonate, makes it a key component in construction materials like cement and limestone.

Tungsten has the highest melting point of all known elements at 3422°C (6192°F). This unique property makes tungsten crucial in applications requiring extreme heat resistance, such as in light bulb filaments and cutting tools. Its atomic structure, with a high atomic number (74), contributes to strong metallic bonding, leading to high thermal and mechanical stability. This high melting point also explains why tungsten is often alloyed with other metals to enhance the strength and durability of materials exposed to high temperatures in various industrial processes.

There are 94 naturally occurring elements, meaning they exist in nature without human intervention. These range from hydrogen, the lightest element, to plutonium. The atomic numbers of naturally occurring elements go from 1 to 94, and the ones beyond this range are synthetically produced. Some elements are abundant on Earth, like oxygen and silicon, while others, like uranium, are rare. The discovery and classification of these elements have greatly influenced chemistry, allowing us to understand the material composition of the universe and its underlying atomic structure.