diff --git a/nqueenproblem.c b/nqueenproblem.c
new file mode 100644
index 0000000..de96399
--- /dev/null
+++ b/nqueenproblem.c
@@ -0,0 +1,80 @@
+#include<stdio.h>
+#include<conio.h>
+#include<math.h>
+#include<stdlib.h>
+int a[30],count=0;
+int place(int pos)
+ {
+	int i;
+	for (i=1;i<pos;i++) 
+	{
+		if((a[i]==a[pos])||((abs(a[i]-a[pos])==abs(i-pos))))
+		   return 0;
+	}
+	return 1;
+}
+void print_sol(int n)
+ {
+	int i,j;
+	count++;
+	printf("\n\n->Solution #%d:\n",count);
+	for (i=1;i<=n;i++) 
+	{
+		for (j=1;j<=n;j++) 
+		{
+			if(a[i]==j)
+			{
+			    printf("\tQ\t"); 
+			}
+			else
+			{
+			    printf("\t*\t");
+			}
+		}
+		printf("\n");
+	}
+}
+
+void queen(int n)
+ {
+	int k=1;
+	a[k]=0;
+	while(k!=0)
+	 {
+		a[k]=a[k]+1;
+		while((a[k]<=n)&&!place(k))
+		   a[k]++;
+		if(a[k]<=n) 
+		{
+			if(k==n)
+			    print_sol(n);
+			 else 
+			 {
+				k++;
+				a[k]=0;
+			 }
+		}
+		 else
+		   k--;
+	}
+}
+
+void main()
+ {
+	int c,n;
+	l:system("cls");
+	count=0;
+	printf("-->Enter the number of Queens\n");
+	scanf("%d",&n);
+	queen(n);
+	printf("\n-->Total possible solutions=%d",count);
+	printf("\n-->Enter 1 to for again or any key for exit:-\n");
+	scanf("%d",&c);
+	switch(c)
+	{
+		case 1:goto l;
+				break;
+		default:printf("-->Program is exited Sucessfully"); 
+				exit(0);
+	}
+}
diff --git a/periodic_table.c b/periodic_table.c
new file mode 100644
index 0000000..b1aa968
--- /dev/null
+++ b/periodic_table.c
@@ -0,0 +1,358 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <conio.h>
+#define TABLE_SIZE 10
+struct node
+{
+	int Atomic_no;
+	char symbol[5];
+	char Element[30];
+	float Atomic_mass;
+	int group;
+	char temp;
+	struct node *next;
+};
+
+struct node *head[TABLE_SIZE] = {NULL}, *c;
+
+void user_get(int Atomic_no, char symbol[], char Element[], float Atomic_mass, int group);
+void insert(int Atomic_no, char symbol[], char Element[], float Atomic_mass, int group);
+void delet();
+void search();
+void display();
+
+int main()
+{
+	char symbol[5], Element[30], v[20];
+	int Atomic_no, group, choice, i, n, l = 0;
+	float Atomic_mass;
+	insert(1, "H", "Hydrogen", 1.008, 1);
+	insert(2, "He", "Helium", 4.003, 18);
+	insert(3, "Li", "Lithium", 6.941, 1);
+	insert(4, "Be", "Beryllium", 9.012, 2);
+	insert(5, "B", "Boron", 10.811, 13);
+	insert(6, "C", "Carbon", 12.011, 14);
+	insert(7, "N", "Nitrogen", 14.007, 15);
+	insert(8, "O", "Oxygen", 15.999, 16);
+	insert(9, "F", "Fluorin", 18.998, 17);
+	insert(10, "Ne", "Neon", 20.18, 18);
+	insert(11, "Na", "Sodium", 22.99, 1);
+	insert(12, "Mg", "Magnesium", 24.305, 2);
+	insert(13, "Al", "Aluminium", 26.982, 13);
+	insert(14, "Si", "Silicon", 28.086, 14);
+	insert(15, "P", "Phosphorus", 30.974, 15);
+	insert(16, "S", "Sulfur", 32.065, 16);
+	insert(17, "Cl", "Chlorine", 35.453, 17);
+	insert(18, "Ar", "Argon", 39.948, 18);
+	insert(19, "K", "Potassium", 39.098, 1);
+	insert(20, "Ca", "Calcium", 40.078, 2);
+	insert(21, "Sc", "Scandium", 44.956, 3);
+	insert(22, "Ti", "Titanium", 47.867, 4);
+	insert(23, "V", "Vanadium", 50.942, 5);
+	insert(24, "Cr", "Chromium", 51.996, 6);
+	insert(25, "Mn", "Manganese", 54.938, 7);
+	insert(26, "Fe", "Iron", 55.845, 8);
+	insert(27, "Co", "Cobalt", 58.933, 9);
+	insert(28, "Ni", "Nickel", 58.693, 10);
+	insert(29, "Cu", "Copper", 63.546, 11);
+	insert(30, "Zn", "Zinc", 65.39, 12);
+	insert(31, "Ga", "Gallium", 69.723, 13);
+	while (1)
+	{
+
+		printf("\n----------------------------------------------------------------\n\n");
+		printf("\t\t1 Add new Element\n");
+		printf("\t\t2 Delete Element\n");
+		printf("\t\t3 Search Element details\n");
+		printf("\t\t4 Display\n");
+		printf("\t\t5 Exit \n");
+		printf("\n----------------------------------------------------------------\n");
+		printf("\n\t\tEnter your choice from above list   :  ");
+		gets(v);
+		l=0;
+		do
+		{
+			if (!isdigit(v[l]))
+			{
+				printf("\n\t\t ERROR !!! ONLY POSITIVE INTEGER ARE ALLOW\n");
+				printf("\n\t\tEnter your choice from above list   :  ");
+				gets(v);
+				l = 0;
+			}
+			else
+				l++;
+		} while (v[l] != '\0');
+		choice = atoi(v);
+		switch (choice)
+		{
+		case 1:
+			user_get(Atomic_no, symbol, Element, Atomic_mass, group);
+			break;
+		case 2:
+			delet();
+			break;
+		case 3:
+			search();
+			break;
+		case 4:
+			display();
+			break;
+		case 5:
+			exit(0);
+			break;
+		default:
+			printf("!!!!!!   ERROR  !!!!!!!!! Enter valid number ");
+		}
+	}
+}
+
+void user_get(int Atomic_no, char symbol[], char Element[], float Atomic_mass, int group)
+{
+	int l = 0, m = 0, n = 0, i, k;
+	char v[20], a[20], b[20];
+	struct node *newnode = (struct node *)malloc(sizeof(struct node));
+label:
+	fflush(stdin);
+	printf("Enter a Atomic Number : ");
+	gets(v);
+	l = 0;
+	do
+	{
+		if (!isdigit(v[l]))
+		{
+			printf("\n\t\t ERROR !!! ONLY POSITIVE INTEGER ARE ALLOW\n");
+			printf("Enter a Atomic Number : ");
+			gets(v);
+			l = 0;
+		}
+		else
+			l++;
+	} while (v[l] != '\0');
+	Atomic_no = atoi(v);
+	k = Atomic_no;
+	i = Atomic_no % TABLE_SIZE;
+	if (head[i] == NULL)
+	{
+		printf("\nSearched element not found\n");
+	}
+	else
+	{
+		for (c = head[i]; c != NULL; c = c->next)
+		{
+			if (c->Atomic_no == k)
+			{
+				printf("\n!!!!!!!!!  This Atomic Number is Exist !!!!!!!!\n");
+				goto label;
+			}
+		}
+	}
+	newnode->Atomic_no = Atomic_no;
+
+	printf("Enter a symbol : ");
+	gets(symbol);
+	strcpy(newnode->symbol, symbol);
+
+	printf("Enter Element full name : ");
+	gets(Element);
+	strcpy(newnode->Element, Element);
+
+	printf("Enter Atomic Mass : ");
+	scanf("%f", &Atomic_mass);
+	newnode->Atomic_mass = Atomic_mass;
+	fflush(stdin);
+
+	printf("Enter the group of Element : ");
+	gets(b);
+	n=0;
+	do
+	{
+		if (!isdigit(b[n]))
+		{
+			printf("\n\t\t ERROR !!! ONLY POSITIVE INTEGER ARE ALLOW\n");
+			printf("Enter the group of Element : ");
+			gets(b);
+			n = 0;
+		}
+		else
+			n++;
+	} while (b[n] != '\0');
+	group = atoi(b);
+	newnode->group = group;
+
+	if (head[i] == NULL)
+	{
+		head[i] = newnode;
+	}
+	else
+	{
+		c = head[i];
+		while (c->next != NULL)
+		{
+			c = c->next;
+		}
+		c->next = newnode;
+	}
+}
+
+void insert(int Atomic_no, char symbol[], char Element[], float Atomic_mass, int group)
+{
+	int i;
+	i = Atomic_no % TABLE_SIZE;
+	struct node *newnode = (struct node *)malloc(sizeof(struct node));
+	newnode->Atomic_no = Atomic_no;
+	strcpy(newnode->symbol, symbol);
+	strcpy(newnode->Element, Element);
+	newnode->Atomic_mass = Atomic_mass;
+	newnode->group = group;
+	newnode->next = NULL;
+	if (head[i] == NULL)
+	{
+		head[i] = newnode;
+	}
+	else
+	{
+		c = head[i];
+		while (c->next != NULL)
+		{
+			c = c->next;
+		}
+		c->next = newnode;
+	}
+}
+
+void delet()
+{
+	
+	struct node *temp1 = NULL, *follow = NULL;
+	int l = 0, d_ele, i;
+	char v[20];
+	fflush(stdin);
+	printf("Enter the Atomic number you want to delete : ");
+	gets(v);
+	l=0;
+	do
+	{
+		if (!isdigit(v[l]))
+		{
+			printf("\n\t\t ERROR !!! ONLY POSITIVE INTEGER ARE ALLOW\n");
+			printf("\nEnter the Atomic number you want to delete : ");
+			gets(v);
+			l = 0;
+		}
+		else
+			l++;
+	} while (v[l] != '\0');
+	d_ele = atoi(v);
+	i = d_ele % TABLE_SIZE;
+	if (head[i] == NULL)
+	{
+		printf("\nElement not Exist\n");
+	}
+	else
+	{
+		temp1 = head[i];
+		while (temp1 != NULL)
+		{
+			if (temp1->Atomic_no == d_ele)
+			{
+				follow->next = temp1->next;
+				free(temp1);
+				printf("\n%d deleted Successfully \n", d_ele);
+				break;
+			}
+			else
+			{
+				follow = temp1;
+				temp1 = temp1->next;
+				if (follow->next == NULL)
+				{
+					printf("\nRecord Not Exist \n");
+				}
+			}
+		}
+	}
+}
+void search()
+{
+	int key, index, l = 0;
+	char v[20];
+	fflush(stdin);
+	printf("Enter Atomic No for get properties : ");
+	gets(v);
+	l=0;
+	do
+	{
+		if (!isdigit(v[l]))
+		{
+			printf("\n\t\t ERROR !!! ONLY POSITIVE INTEGER ARE ALLOW\n");
+			printf("Enter Atomic No for get properties : ");
+			gets(v);
+			l = 0;
+		}
+		else
+			l++;
+	} while (v[l] != '\0');
+	key = atoi(v);
+
+	index = key % TABLE_SIZE;
+	if (head[index] == NULL)
+	{
+		printf("\nSearched element not found\n");
+	}
+	else
+	{
+		for (c = head[index]; c != NULL; c = c->next)
+		{
+			if (c->Atomic_no == key)
+			{
+				printf("\n---------------------------------------------------------\n");
+				printf("\t\t\tAtomic Number : %d\n\t\t\tSymbol : %s\n\t\t\tElement Name : %s\n\t\t\tAtomic mass : %.3f\n\t\t\tGroup : %d", c->Atomic_no, c->symbol, c->Element, c->Atomic_mass, c->group);
+				printf("\n---------------------------------------------------------\n");
+				break;
+			}
+		}
+		if (c == NULL)
+
+		{
+			printf("\nSearched element not found\n");
+		}
+	}
+}
+
+void display()
+{
+	int key, l = 0;
+	char v[20];
+	fflush(stdin);
+	printf("Enter index of 0 to 9  : ");
+	gets(v);
+	l=0;
+	do
+	{
+		if (!isdigit(v[l]))
+		{
+			printf("\n\t\t ERROR !!! ONLY POSITIVE INTEGER ARE ALLOW\n");
+			printf("Enter index of 0 to 9  : ");
+			gets(v);
+			l = 0;
+		}
+		else
+			l++;
+	} while (v[l] != '\0');
+	key = atoi(v);
+	if (key < 10 && key >= 0)
+	{
+		for (c = head[key]; c != NULL; c = c->next)
+		{
+			printf("\n---------------------------------------------------------\n");
+			printf("\t\t\tAtomic Number : %d\n\t\t\tSymbol : %s\n\t\t\tElement Name : %s\n\t\t\tAtomic mass : %.3f\n\t\t\tGroup : %d", c->Atomic_no, c->symbol, c->Element, c->Atomic_mass, c->group);
+			printf("\n---------------------------------------------------------\n");
+		}
+	}
+	else
+	{
+		printf("\n!!!!!!!!!!!!!!!!!!!  Enter the index between 0 to 9!!!!!!!!!!! ");
+	}
+}